Tag: Japanese Maple

The upright, rounded habit with weeping branches gives a graceful profile that makes a striking focal point for foundations, islands, mixed shrub beds, or patio planters, and it’s among the best for retaining its vibrant burgundy shading in full sun.

The lacy, deeply dissected leaves give a long-lasting and impressive show.

They emerge bright cherry red in spring, deepen to a dark, delicious merlot or plum color for summer, then brighten to a stunning cerise for fall’s foliage finale.

And in winter, the dense frame of handsome, red-stemmed twiggy branches are made for a string of holiday twinkle lights!

If your garden’s ready for an infusion of red-toned sophistication, let’s jump into how to grow ‘Red Dragon’ Japanese maple!

Here’s what you’ll find ahead:

What Is ‘Red Dragon’ Japanese Maple?

‘Red Dragon’ is a dwarf cultivar of Acer palmatum var. dissectum, also known as laceleaf, cutleaf, threadleaf, or weeping Japanese maples.

A. palmatum is a popular species that hails from Japan and eastern China. And the variety name, dissectum, refers to the shape of the foliage.

The leaves are deeply cut with a delicate, feathery nature – apparently, they resemble a dragon’s claws, hence the colorful cultivar name!

These deciduous trees have a mature height and spread of six to 10 feet – smaller when grown in containers, usually three to five feet – with a strong, central leader stem and multiple branches in an open, rounded form with a weeping habit.

Along with the graceful form, ‘Red Dragon’ shines for its three seasons of color-changing foliage.

New growth is bright red with the leaves deepening to burgundy in summer, then brightening again once frosty temperatures arrive.

‘Red Dragon’ retains its red hues in summer better than most Japanese maples.

In spring, small, inconspicuous flower corymbs appear, maturing into burgundy samaras in late summer to early fall.

Samaras are the two-winged, seed-containing whirligigs that spin as they travel on the wind.

The plants also provide winter interest with an attractive, multi-branched silhouette, and coarse, grayish bark on the leader and main branches plus red stem tips.

These compact trees typically have a clearance of about three feet from the ground and grow at a slow rate. But they are long-lived, with a lifespan of up to 80 years.

Their upright and weeping growth adds unique beauty to protected sites throughout the landscape and ‘Red Dragon’ can handle full sun in temperate areas, although light afternoon shade is recommended in regions with intense afternoon sunshine.

They have moderate cold hardiness and are suitable for growing in Zones 5 to 8.

Cultivation and History

The islands and territories of Japan are home to 23 known species in the Acer genus, but the many beautiful landscape specimens known as Japanese maples come mainly from two species, A. palmatum and A. japonicum.

Development of the ornamental cultivars started in Japan in the early 1600s, but it wasn’t until the end of the 1700s that they were introduced to Europe, making their way to North America by the mid-1800s.

Easily cultivated with few problems, today Japanese maples are a welcome addition to small yards or large landscapes.

Dwarf Japanese maple varieties like ‘Red Dragon’ and ‘Crimson Queen’ make a striking focal point for compact spaces such as city and courtyard gardens, foundations, nooks and islands, or as an impressive spiller in large containers and patio planters.

‘Red Dragon’ Japanese Maple Propagation

For the home gardener, ‘Red Dragon’ Japanese maple trees are best propagated from softwood stem cuttings or via grafting.

Starting trees from seed is possible, but because the original stock was most likely grafted, the seedlings they produce won’t be true to the parent.

Here’s how to start softwood cuttings:

Take softwood cuttings in mid-spring, four to eight weeks after new growth emerges.

Use clean, sharp shears to remove six- to eight-inch tips from softwood stems that have hardened slightly.

Remove leaves from the bottom half of the cuttings but keep the tip leaves intact.

To improve chances of rooting, dip the cut end in a rooting hormone powder. Shake gently to remove excess powder.

Fill six-inch pots with a rooting soil blend or make your own from equal parts of coir or peat moss, landscape sand, and perlite.

Water lightly to moisten the soil mix but don’t saturate it.

Insert the cut ends halfway up the stem and firm the soil carefully around them to keep them in place.

Set the cuttings in a site that receives bright, indirect light. Water daily with a gentle mist setting.

Roots should develop within three to four weeks.

Our guide to growing Japanese maples covers this process in detail.

In fall, plant your new saplings into 12-inch pots to give them another year of growth before planting out into garden beds or a permanent container.

If you’d like to try your hand at grafting, our guide to grafting Japanese maples has all the details.

Transplanting

The easiest way to get started is to purchase a plant from a garden center or nursery and transplant it into the garden.

Fall is the best time to plant as it gives the roots time to get established while the rest of the tree is dormant, but spring works as well.

And if you receive a lot of winter rain, planting in a raised mound can be a good idea. Elevating the roots in a mound helps to avoid standing water and improves drainage. Mounds should be at least 18 inches above the garden soil level.

Loosen the soil in the planting site to a depth of 18 inches.

To your garden soil, mix in one part of compost, well-rotted manure, or worm castings to enrich the soil – Acer species do best with moderate amounts of nutrient rich organic materials.

Mix in one part landscape sand, pea gravel, or stone chips to give the plants the sandy texture they prefer and to improve soil drainage.

Add in one part of moisture-retentive material, like coconut coir, peat moss, perlite, or vermiculite to help keep the soil lightly moist.

Create a planting hole three times the width and one to one and a half times the depth of the root ball.

Fill the hole with water and then let it drain.

Carefully remove the tree from the nursery pot and gently loosen some of the feeder roots from the top of the root ball only, but don’t try to spread them all out before planting.

Set your tree in place with the top of the root ball level with the soil line or up to four inches above it – the faster your soil drains, the closer to the soil line the top of the root ball can be.

After checking that the leader trunk is straight, backfill with soil, firming it gently in place.

Water gently but deeply so that the entire root ball gets a drink.

How to Grow ‘Red Dragon’ Japanese Maple

‘Red Dragon’ is best grown in lightly moist, organically rich, well-draining soil with a sandy loam texture and slightly acidic pH of 6.0 to 6.5.

It grows in full sun to part shade, but the foliage can suffer from scorch in areas with hot summers, especially if the soil isn’t kept consistently moist.

A site with light afternoon shade is beneficial for areas that experience intense afternoon sunlight.

Japanese maples are also prone to scorch from other environmental stressors like overly dry soil and hot, drying winds, and this is particularly true for cultivars with highly dissected leaves, like ‘Red Dragon.’

The deep cuts in the foliage create a large surface area for maximum moisture absorption, but they’re also fast to dry out in hot winds, causing the leaves to brown and curl.

Choose a sheltered growing site that can provide protection from drying winds.

After planting, water new trees regularly to help them become established, and water weekly in summer, in the absence of rain to maintain good health.

Once established, keep the soil evenly and lightly moist. A steady supply of moisture keeps the thin, delicate leaves well-hydrated and helps to prevent burning and drying out.

Container Grown Plants

‘Red Dragon’ is ideal for growing in large containers and patio planters.

It has a compact size to start with and Japanese maples are “self stunting,” which means that the canopy growth slows when the roots are confined.

The results are that they can stay in the same pot for years without sizing up or pruning the roots. The one in the photo above has been in the same pot for 25 years with no problems!

Choose a container that’s two or three times the volume of the root ball and ensure it has drainage holes – these trees are sensitive to soggy soil and can easily develop root rot in wet conditions.

I like to add a two-inch layer of porous drainage material over the drainage holes to keep the water moving and avoid issues like wet soil. Materials such as broken pottery or pebbles work well for this.

Fill the container to three quarters with a good quality potting soil. Or you can mix your own blend.

Use two parts loamy garden soil; and add one part compost, manure, or worm castings for nutrients; one part gritty material for drainage; and one part moisture retentive materials to help keep the soil lightly moist.

Water the soil in the pot and let it drain away through the holes in the bottom.

Remove the tree from its nursery pot and set into place, ensuring the leader trunk is straight.

Add more soil to cover the roots leaving the top of the root ball level with the soil line or about two inches above it. Firm the soil gently in place and water deeply.

Add a layer of mulch to help keep the soil lightly moist and water when the top of the soil dries out, watering deeply.

Read our guide to learn more about growing Japanese maples in containers.

Growing Tips

Easily cultivated ornamentals, the following tips will help your ‘Red Dragon’ to thrive!

• Plant in a site with at least six hours of sunlight per day for the best leaf coloration. 
• For the most attractive leaves, provide them with a site sheltered from strong winds.
• Water regularly to keep the soil evenly moist.

Pruning and Maintenance

‘Red Dragon’ does an admirable job of retaining an attractive shape and requires very little in the way of pruning.

If pruning is required, do so in late fall to mid-winter, but a light summer trim is also acceptable. However, avoid pruning in temperatures above 80°F – the previously shaded bark may be tender and prone to sun scald.

In winter, it’s easier to see the branches to make the cuts needed to lift the canopy. But in summer, you get a better idea of where the thinning needs to happen if you want to expose more of the interior.

It’s also important to not remove more than a quarter of the tree’s crown or more than a quarter of the leaves on any individual branch at any one time.

Removing more than these amounts can cause unnecessary stress and starve the tree of nutrients.

In late winter, use your fingers or a small hand rake to groom the branches and remove any dead leaves still clinging to them.

At the same time, remove any dead branches using clean, sharp shears or a small garden saw.

To lift the canopy or branches dragging on the ground, follow the stem’s tip up to a strong side branch, removing the lower branch just below the junction.

Learn more about pruning Japanese maples in our guide.

When grown in a full sun location, the canopy usually becomes fully foliated. In partial shade, it remains open and airy, exposing some of the tree’s “bones” in layers or tiers – a cultured look often found in botanical or display gardens.

To create a cascading, fan-like profile, in summer, trim the branches lightly into overlaid tiers that arch over the next layer, but don’t touch.

Use clean, sharp shears to trim away small branches that are touching or crowding the next lowest layer. But use a light touch to prevent stress. It’s better to sculpt your tree over a period of two or three years than to remove too much in a single season.

To help maintain evenly moist soil, in summer apply a two or three inch layer of mulch, using materials such as shredded bark, conifer needles, chopped leaves, leaf mold, pebbles, or straw.

Provide your trees with good air circulation on all sides, trimming lightly to open the canopy or to lift the bottom branches off the ground if needed.

To avoid wet soil, it must be well-draining. Amend the soil with gritty material like landscape sand, pea gravel, or stone chips to improve drainage or plant trees in an elevated mound.

Ensure containers have drainage holes and avoid overwatering.

Also, the use of a drip irrigation system is helpful to avoid splashing water and pathogens onto the leaves.

If needed, spray your tree with a natural fungicide like neem oil to control problems.

You can learn more about common Japanese maple diseases in our guide.

Potential pest problems you may come across include aphids, beetles, and scale. Our guide to managing common Japanese maple pests can help you resolve any issues.

Best Uses for ‘Red Dragon’ Japanese Maple

The fine, fern-like leaves of ‘Red Dragon’ have a light, delicate look and give a beautiful texture to the landscape.

The trees can tolerate partial shade, and with their compact size and airy form, they’re the ideal understory plant for adding color and privacy without crowding in borders and screens.

Massed in a row, they provide a colorful border or seasonal hedge.

And as a standalone accent, ‘Red Dragon’ makes a striking focal point for foundations, islands, and mixed shrub beds. Add some companion plants for added garden interest.

They’re ideal for containers and planters on balconies, decks, and patios or throughout the garden, adding color, height, and texture. And can even be trained as bonsai.

The leaves emerge bright purple red in the spring, take on a deep burgundy hue all summer, before changing to fiery red in the fall.

Though they lack leaves in the winter, the naturally open, rounded canopy provides its own interest.

Excited to try this perennial favorite in your garden? I get it! It was the gateway to my Japanese maple addiction, too.

We’re going to cover all you want to know about growing this cultivar in this guide. Here’s what’s on the menu:

Cultivation and History

If you assumed that the name ‘Bloodgood’ comes from the blood-red color of the foliage, you wouldn’t be the first, nor will you be the last. It doesn’t, though.

This cultivar is named after the Bloodgood Nursery in Long Island, New York where it was bred.

The history of how ‘Bloodgood’ came to be isn’t totally clear. We know for sure that it was bred by Bloodgood Nursery, which was founded in 1793, and it was introduced to market shortly after the Civil War.

If you know your Japanese history, you’ll remember that Japan wasn’t openly trading with the West during that period, so there’s some question about how the original parent specimen or specimens that found their way to New York.

They may have come via the Netherlands from Nagasaki, Japan, which had the single open trading port in the country during that period.

To be clear, not every ‘Bloodgood’ on the market today is a direct descendent of the original New York tree or trees. Many are strains or clones of trees in the Atropurpureum group.

In other words, Bloodgood can be a generic name for a specimen that looks like the original. If you’d like to know more about the different groupings of Japanese maples, read our guide.

True ‘Bloodgood’ trees are hardy in Zones 5b to 8b, and have a neat, rounded canopy on a plant that grows about 20 feet tall and wide.

The red or purple leaves have serrated margins and a palmate shape, each with seven lobes. In the fall, they turn bright red. In hot regions, the foliage will turn bronze or take on a green hue.

In the fall, when the leaves turn a brighter red, they lose any summer bronzing that might have developed.

‘Bloodgood’ Japanese Maple Propagation

You can try to propagate ‘Bloodgood’ from seed, but the resulting tree might not be anything like the parent.

If you want to be sure of what you’re growing, you’ll want to use grafting or cuttings, both methods produce a clone of the parent plant.

Taking cuttings involves removing a length of stem and planting it in soil to encourage it to form roots. Our guide to growing Japanese maples covers all the details about how to take and plant cuttings.

Grafting is the go-to propagation method for many Japanese maple lovers. It’s reliable and works well with these trees.

You will combine the scion, or top part, with the rootstock, the bottom part that includes the roots. Learn about the whole process of grafting Japanese maples in our guide.

The easiest way to get started is to purchase a specimen from a nursery or big box store and transplant it into the garden.

Dig a large hole, at least twice as wide as the root ball, and ensure the plant is sitting at the same level it was in its growing container.

How to Grow ‘Bloodgood’ Japanese Maples

Plant in full sun or a bit of afternoon shade. Many red Japanese maples lose their bright coloration in full sun. ‘Bloodgood’ generally doesn’t, though it can bronze a bit.

The good news is that if you live in a hot climate, it’s perfectly fine in partial sun. Give it a spot with a little shade protection in the hottest of the afternoon heat, and you can avoid any bronzing.

In the southern end of its hardiness range, the leaves might turn green during the heat of the summer. This is nothing to worry about and there isn’t much you can do beyond providing some afternoon shade and waiting for the fall colors to arrive.

In the spring, red-winged fruits hang from the tree and can last until the summer. These will gently spin to the ground. There aren’t a ton of them and they are fairly small, so they aren’t as noticeable or annoying as other maple samaras, as they’re called.

Though they prefer loose, loamy soil, with a pH of 6.0 and 7.0, these trees can grow in clay so long as the ground is sloped so the excess moisture can run off. Well-draining soil is non-negotiable for the health of these trees.

In addition to taking care not to overwater, you also need to make sure that they don’t get too thirsty.

You want to find a happy medium where the roots are able to just dry out, which encourages them to stretch and grow outwards. But don’t let the roots stay dry for too long, as this causes stress.

Water when the top two or three inches of soil are dry to the touch. Specimens growing in full sun in hot regions will likely need more water than those in cooler areas.

Young trees should be watered a bit more frequently so that the soil a few inches down doesn’t dry entirely.

Almost any Japanese maple can be grown in a container, but some are better suited to this than others. ‘Bloodgood’ can grow very large so it will take a little extra work to keep the tree contained, meaning you’ll need to remove it from the pot and trim the roots regularly.

We have a whole guide to growing Japanese maples in containers if you’d like to give it a go.

Speaking of, if you want to take things one step further and grow yours as a bonsai, we have a guide for that, too. ‘Bloodgood’ is a popular option for gardeners just starting out in the world of bonsai, both because it’s readily available and it has a nice form and color.

Don’t fertilize your plant in the first year after planting and if you propagated it via a stem cutting, make that two years.

From the second year onwards, feed in the early spring with compost, humus, or a slow-release fertilizer. Learn more about how to fertilize Japanese maples in our guide.

Pruning and Maintenance

‘Bloodgood’ doesn’t need any special pruning beyond what is typical of Japanese maples. You can learn more about pruning Japanese maples in our guide.

Generally, you should prune off broken, diseased, or deformed branches any time you see them. Otherwise, shaping and maintenance pruning should be done in the winter.

If you want to provide shape, you will need to work to open up the crown and make the shape look appealing.

It can take ten years or more for the tree to mature, so it could be a long time before you need to do much in the way of pruning.

But once mature, you might want to prune out some of the lower branches to give it a more classic “tree-like” shape and to show off the shape and texture of the trunk.

If you’d like to maintain that natural globose canopy shape that many people specifically choose this cultivar for, don’t trim out the lower branches. Just focus on removing anything that detracts from the round shape.

Be sure to remove any branches that have a tight crotch causing the bark of the branch to embed itself in the trunk. These embedded branches will eventually cause splitting in the trunk.

Use caution when mowing around the trees because damage to the base can lead to diseases and might even kill a tree.

For the most part, the damage they cause is largely cosmetic, but a young tree can be seriously stunted or damaged.

But some beetles can chew into the wood, causing serious damage. To learn more about Japanese maple pests and how to deal with them, check out our guide.

When it comes to diseases, there are quite a few that can be a problem. Everything from the dreaded anthracnose and leaf spot to powdery mildew and verticillium wilt can take down a tree.

Learn more about all of these and a few other challenges in our guide to Japanese maple diseases.

Best Uses for ‘Bloodgood’ Japanese Maples

‘Bloodgood’ is unparalleled as a specimen planting. It acts as a highlight and a focal point to any garden, whether it’s Japanese style or an English cottage garden. It’s a popular choice for bonsai, as well.

It works in borders, in containers, or trained as standards. ‘Bloodgood’ is perfect next to walkways, decks and patios because the roots aren’t pushy, it doesn’t make a big mess, and it offers shade.

Japanese maples make marvelous companions, and ‘Bloodgood,’ with its reliably ruddy foliage, is especially so.

Pair it with something green like arborvitae (Thuja spp.), juniper (Juniperus spp.), ferns, or Japanese black pine (Pinus thunbergii).

Or you could put it next to something that will pop, like dogwood (Cornus spp.), snowbells (Styrax japonicus), or peonies (Paeonia spp.).

Check out our guide for more information about companion planting with Japanese maples.

Armed with the knowledge of what to look for, you can save your Japanese maples, or even keep them from contracting a disease in the first place.

That’s why we’ve whipped up this guide on the most common illnesses of A. palmatum. How to identify them, how to manage them, how to prevent them… it’s all covered here.

Here’s the list of diseases:

If you’re in need of a refresher about how to grow Japanese maples, be sure to check out our guide.

1. Anthracnose

Fun fact about the word “anthracnose”: it’s a catch-all term for a group of related fungal diseases that usually cause darkened foliar lesions.

And anthracnose can infect many plants, including Acer species such as Japanese maples.

Several fungal pathogens can cause anthracnose in Japanese maples – Aureobasidium apocryptum, Discula campestris, and Colletotrichum gleosporoides are a few significant ones.

Overwintering in dead leaves, twigs, and buds, the pathogens produce fruiting bodies in spring, which release spores that spread via wind and rainwater to uninfected structures.

Once infected, Japanese maple foliage exhibits tan or black blotches along leaf margins and primary veins. Infected foliage will then turn necrotic, curl, and drop.

In time, this can defoliate trees prematurely, as well as lead to the decline of stressed, weak, young, and/or recently transplanted Japanese maples. 

Since spores spread via splashing water and wind, avoid overhead irrigation and sufficiently space trees when you plant.

Infected leaves and branches should be promptly pruned and destroyed, while dropped leaves, branches, and other bits of detritus should be removed to prevent pathogen overwintering and further spread.

For at-risk Japanese maple trees, preventative fungicide sprays in early spring can help. Start at bud break, and repeat twice at two-week intervals. Be sure to follow the label’s instructions!

2. Canker

If you’re a bit squeamish, feel free to skip this one.

Cankers result from open wounds becoming infected by fungal or bacterial pathogens. Capable of appearing on any part of a Japanese maple tree’s bark, cankers tend to be brown to reddish, sunken, and irregularly-shaped.

They also ooze moist sap, as well as stink something awful.

The foliage beyond a canker can become stunted, chlorotic, browned, and curled.

In time, the pathogen can spread into a tree’s vascular system, which can cause further wilt and branch dieback.

Plus, a canker can produce its own spores, which spread in wet and windy conditions to form more cankers elsewhere.

Canker prevention is simple: avoid unnecessarily wounding your Japanese maple and keep it healthy. Also, be sure to regularly sterilize your gardening tools rubbing alcohol.

For a Japanese maple currently carrying cankers, prune away infected branches several inches behind the symptomatic tissue.

Be sure to dispose of them promptly, and only make your cuts in dry weather with sharp, sterile blades. To address cankers on the trunk, you should consult an arborist or plant pathologist.

3. Leaf Scorch

Leaf scorch is technically an abiotic condition, meaning it’s a physiological condition caused by the environment, rather than a biological pathogen.

Caused by high temperatures, dry winds, low soil moisture, or some combination of these, leaf scorch manifests in brown or gray foliar margins, as well as chlorotic or darkened areas between leaf veins. In time, scorched foliage can turn brown, dry, and brittle.

In mild cases, the foliage can survive with only a bit of disfigurement. More severe cases will cause premature defoliation, as well as twig drop.

Either way, symptoms tend to be stronger on the side of the Japanese maple tree that’s most exposed to wind and sunlight.

Thankfully, leaf scorch is usually a temporary condition caused by a hot, dry summer. But if leaf scorch happens year after year, then your tree may lose vigor and become a bit stunted.

Preventing and halting leaf scorch are both pretty simple: provide proper irrigation and moisture-retaining mulch.

As long as you work to counteract the moisture loss with enough water, the leaf-scorched Japanese maple should produce beautiful leaves next spring like nothing even happened.

4. Phyllosticta Leaf Spot

Phyllosticta leaf spot is pretty easy to notice. Or “spot,” if you’ll pardon the pun.

It’s caused by the fungus Phyllosticta minima, which overwinters in fallen foliar detritus. In spring, it produces spores that spread via wind and splashing water to the budding foliage of nearby A. palmatum specimens. 

New spores produced on infected foliage can then spread throughout the canopy, or even move to nearby trees. In serious cases, the Japanese maple can be defoliated for a time, but the leaves will typically grow back.

Infected leaves exhibit yellowish to tan spots, with dark reddish to purplish borders.

The centers can sometimes be transparent or even drop out, leaving infected foliage with more shot holes than a John Wick background actor.

Take a closer look at the leaves and you’ll notice black fruiting bodies in the dead sections.

It’s important to rake up nearby foliar detritus in fall to remove sites for overwintering pathogens.

Overhead irrigation should be avoided, along with placing specimens too closely together. If you notice severely infected leaves, pruning them can help limit spread.

Preventative applications of fungicides can be helpful for young, previously diseased, or otherwise at-risk Japanese maples.

Three applications should suffice: one at bud break, one about 10 days later, and one when the foliage is fully formed.

5. Phytophthora Root Rot

Some truly horrible things start with “ph,” such as phonies, phishing, and phlegm. Phytophthora root rot, caused by water molds in the Phytophthora genus, is another.

As with most root rots, Phytophthora begins with too much moisture, whether your Japanese maple receives too much water, the soil it’s sitting in doesn’t drain well, or both.

When the soil is excessively soggy, it serves as the perfect environment for the soil-borne resting spores of Phytophthora species to germinate and produce motile spores.

These motile spores spread via free water to penetrate roots, trunks, and branches of nearby plants.

Once infected, a Japanese maple will start to look drought-stressed, ironically enough. Leaves turn discolored, bark darkens, roots turn necrotic, and the plant as a whole will decline and eventually die.

Prevention is as simple as not overwatering, providing well-draining soil, and avoiding planting in contaminated soils.

Be sure to select plants that you know are disease-free, and feel free to use foliar sprays of fungicides, which’ll be absorbed and travel down into the roots.

For a specimen that’s already infected, cease supplemental irrigation immediately. If the plant can’t recover on its own, then you’ll have to remove and destroy it.

6. Powdery Mildew

Caused by several genera of closely related fungi, powdery mildew isn’t the grossest of conditions on this list.

If anything, it shows up on leaves looking like a gentle coating of old baby powder, a fine application of moldy parmesan cheese, or perhaps a severe case of dandruff.

Okay, I guess that’s actually pretty nasty.

Whatever you think the grayish-white powder looks like, it spots and coats foliage, leaving it with abnormal growth, distortion, and discoloration. As it progresses, foliar chlorosis, browning, desiccation, and even premature drop can occur, as well as a decline in overall plant health.

Since the fungi survive the winter by living in fallen plant debris before producing spores in spring, it helps to rake up nearby leaves and twig detritus in fall.

And since the spores need cool and humid conditions to spread, avoid overhead irrigation and crowding plants together.

Remove infected foliage and stems as you notice them. You’ll also want to remove any suckers that pop up near the base of the Japanese maple tree – those are especially vulnerable to infection.

Promptly applying fungicides once symptoms are noted can also help to prevent further spread.

You can learn more about powdery mildew in our guide.

7. Pseudomonas Tip Blight

A disease of many ornamental plants, Pseudomonas tip blight can be bad news for a Japanese maple.

This condition is caused by the bacterium Pseudomonas syringae, which overwinters in fallen plant detritus or in the healthy tissue of the plant itself.

In cool and wet spring weather, it spreads via wind, splashed rain, insects, and/or pruning tools to enter plant tissue through wounds or natural openings.

Once inside, the bacteria produces toxins that move through the xylem to cause problems.

Said problems include shoot discoloration, shriveling, and death.

Think of a gangrenous limb in need of amputation, and that’s what infected branches and foliage are like, for the most part. And if enough branches fall victim, then the entire Japanese maple tree can perish.

Be sure to prune away any infected tissues with sterile tools when you notice them, but only during dry weather – the pathogen could spread in moist conditions.

If any infected leaves and twigs drop, rake those up as well. And be sure to avoid high-nitrogen fertilization, which can lead to vulnerable late-season growth.

If the tree is severely infected – i.e. more than half of the crown is symptomatic – then removing and destroying the specimen may be your best bet.

8. Tar Spot

 Just by the name, you can probably imagine how gnarly tar spot looks.

In maples, tar spot is caused by various fungal species from the Rhytisma genus, which overwinter in fallen foliage.

Come spring, the spots split, releasing spores that hitch a ride on wind to nearby foliage. If a leaf becomes infected, tar spots form and the cycle continues.

Said spots tend to show up in late spring to early summer as small, pale yellow areas less than an eighth of an inch in diameter.

Over time, the spots grow and become dark brown or black, with yellow borders. This spotting interferes with photosynthesis, slightly impeding the tree’s growth and development.

Thankfully, tar spot doesn’t really damage the host over the long term, since new leaves will form every year.

Besides raking up and destroying fallen leaves, as well as pruning infected ones as you notice them, you could try using foliar fungicides, aiming for as much coverage as possible.

Learn more about tar spot and other Japanese maple leaf spots in our guide.

9. Verticillium Wilt

A disease of many different trees and shrubs, verticillium wilt afflicts Acer species with a particular ease and severity, to the point that it’s often nicknamed “maple wilt” among arborists.

Verticillium wilt is caused by two fungal species of Verticillium: V. albo-atrum and V. dahliae.

Lying dormant in soil and plant roots, these pathogens move to wounds or natural openings in roots and branches, traveling via flowing water, infested soil, wind, or contaminated pruning tools.

Once inside the plant’s vascular system, the pathogen halts the flow of water and nutrients, leading to foliar wilt, browning, and premature drop.

These symptoms are often limited to specific sections of the tree at first, before spreading throughout the crown.

Infected branch bark exhibits discolored streaks, and the entire Japanese maple can gradually decline before perishing.

It’s important to prune away infected branches ASAP, as far back as the discolored bark tissue goes. Use sterilized pruning tools, and make sure to destroy any pruned material.

If the disease outpaces your pruning efforts and/or afflicts the majority of the tree, you may have to remove and destroy the entire plant.