JM and Trident Leaf Curl

[alexm]

I had lovely leaves growing in spring but the recent leaves on my Japanese and Trident Maples have been curled or deformed. Any ideas what's wrong?

[TimIAm]

Sydney heat? How's your watering been the past couple of weeks? Another day of 30+ degree heat today.

Are they in full sun? Are they in bonsai pots or grow pots or?

Possible combination of heat and insect damage?

Are the leaves dropping or staying on the tree and just look a bit damaged? It looks like a bit of heat damage and bugs. If it's not dropping leaves or showing signs of disease, that would be my guess.

[TimIAm]

Also, it is common for the very ends of new growth to come out looking less than perfect. I've seen this in quite a few species. I suspect it is because the tree tries to extend to maximum growth and the tail end of that growth is at the very tips resulting in the last bit of growth coming out under-developed. I've seen with Chinese Elms, with the spring growth, it will throw out long new growth, but then the last 5% will die off at the tips as it heads into winter.

The growth tips are also more appealing to insects (and possums) and are more susceptible to being scorched in high temps because they are more tender than the inner growth which has had more time to harden off.

Below is just one example of under-developed / misshaped growth at the tips on one of my maples.

IMG_6274.jpg

[alexm]

Thanks Tim. Most are still in grow pots for development but I usually can only get out to water once a day. I couldn't see them in the day but went out tonight and saw a few whitefly. So probably a combo of all your suggestions.

[AndreasM]

We are having an issue with passionvine hoppers in our garden at the moment. They like our JM (and cherry trees, and citrus trees, and hydrangeas, and even a magnolia). THe leaves end up looking very similar - of possible interest, they don't seem to like th fine serrated and red leaves; mostly goign for anything green and, well, leafy. at least they havent attacked my deciduous bonsai yet.

[thoglette]

Looks like normal summer behaviour to me: with the hot dry winds we get here all my JMs suffer significant leaf burn in summer. Like 60% of the foliage. The tridents cope better but still get some peripheral damage.

If it’s happening after dry, windy days, don’t panic.

I remove all the burnt foliage from my JMs in March & the trees as, by that time, it’s cool enough for regrowth and I want the extra light getting into the inner foliage.

Short version: a Mediterranean climate is a stupid place to grow JMs but I do so regardless.

[TimS]

Looks like normal summer behaviour to me: with the hot dry winds we get here all my JMs suffer significant leaf burn in summer. Like 60% of the foliage. The tridents cope better but still get some peripheral damage.

If it’s happening after dry, windy days, don’t panic.

I remove all the burnt foliage from my JMs in March & the trees as, by that time, it’s cool enough for regrowth and I want the extra light getting into the inner foliage.

Short version: a Mediterranean climate is a stupid place to grow JMs but I do so regardless.

Agree, the trident foliage photo at least just looks like generic summer leaf damage to me. The JM distorted leaf could be stress, pest or nutrient induced damage. A careful and close look over will tell you if it's pest related, if you're fertilising with a balanced one you should be fine on the nutrient front but timing with JM is important. I've had distorted leaves on them if i fertilise too early in spring (ie before hardening off when thye're sill extending) but that's about it. If your other tree are showing signs of stress from heat/ wind/ climate related impacts then safe to say it's impacting the JM too.

Only my love of winter silhouette Japanese Maples keeps me bothering to still grow them in costal Melbourne climate as i rarely see anything approaching good autumn colour due to summer damage. Trident is a bit more resilient, but mine is burnt too even under 50% shade cloth as the wind still pulls through there.

[AndreasM]

Looks like normal summer behaviour to me: with the hot dry winds we get here all my JMs suffer significant leaf burn in summer. Like 60% of the foliage. The tridents cope better but still get some peripheral damage.

If it’s happening after dry, windy days, don’t panic.

I remove all the burnt foliage from my JMs in March & the trees as, by that time, it’s cool enough for regrowth and I want the extra light getting into the inner foliage.

Short version: a Mediterranean climate is a stupid place to grow JMs but I do so regardless.

Thank you from my pespective, too. useful to know, once I have all these hoppers killed!