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I recently bought a small red Acer and moved it into a more permanent pot. It's about 2 1/2 feet tall and since I've moved it, the leaves have started to brown and shrivel like a dead leaf would in autumn. The pot is about 1 foot in diameter and 2 feet tall, and has a drainage hole in the bottom about 1 1/2 inch in diameter.

I live in the UK and it's been very warm the last few weeks but we've also had a few downpours. I've watered it a few times but not every night. It's in direct sun from about 10 am to 2 pm.

When I re-potted it I put some large stones in the bottom of the pot for drainage, some sods of grass from tidying the lawn, then some spare soil from the garden, then some compost.

Why is this happening, what have I done wrong and what can I do to fix it?

The following pictures are of the tree in its pot; some shriveled leaves; and also the trunk and lower branches, which look sort of dead, although that part may have been like that originally.

Click on any picture to see a close-up view.

The tree in its pot One leaf Some leaves The trunk

update 08/16/2014

I moved the tree out of the wind and re-potted in potting compost. All the "burned" leaves have fallen off and new buds seem to be appearing.

the relocated tree New buds!

  • Welcome to our site! Are you going to be planting this in your garden or keeping it in a pot? This is a Japanese Maple and can attain heights of 15-20'. – stormy Jul 12 '14 at 3:23
  • Hi @stormy. It's going to be staying in the pot. Thanks – Greg B Jul 12 '14 at 7:04
  • @stormy They don't generally get over 12 feet high in a pot. – J. Musser Jul 13 '14 at 1:00
  • How is the maple doing now? – J. Musser Aug 15 '14 at 4:03
  • I thinks it's doing better :/ see update – Greg B Aug 16 '14 at 10:08
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First, your Acer is not dying, it's just very unhappy. This is a common problem on Acer palmatum varieties here in the UK- usually, the cause is wind, that is, you've placed the plant in a spot which isn't sheltered enough. They hate windy areas, and they don't like hot midday sun in high summer either. What they do like is dappled sunlight, or morning sun, or afternoon sun, just not roasting hot sun in the middle of the day, but a sheltered, non windy spot is critical.

I agree with other's comments about drainage - you may have been watering more to obviate the shrivelled leaves, thinking drought was causing that; that would explain why the soil in the pot looks very damp, but if you have no drainage holes in your pot, it's critical that you make some, or change the pot. If there's a single hole in the bottom, and you've crocked it, that's fine as it is. Water copiously when you see or feel the compost on the top is slightly dry to the touch - but don't wait till it's shrunken from the sides of the pot. It will take a while for your tree to put out roots well into the compost to pick up moisture, so in the meantime, it's a small rootball surrounded by soil which shouldn't be allowed to dry out too much.

A word about compost though - Acer palmatum varieties do not like limey or alkaline growing mediums, and you don't say what you used to pot it up. It doesn't look like there's a compost problem, I'm 100% sure this is a 'not sheltered enough' problem, but if you used something that was alkaline, change the compost. Use ericaceous - they don't really need high acid, but at least you'll know it's not alkaline, and it won't do any harm.

  • Thanks @Bamboo. Interesting you mention wind. The tree is at the end of the passage way between our house and the neighbour which can experience winds up to 80 miles an hour as were on an exposed hill. Also, the tree is in direct and harsh sun through the morning. It's a shame, I'm not sure where else in the garden suites it but I'll have a think and try and get it some shelter from both sun and wind – Greg B Jul 12 '14 at 20:45
  • I agree. Wind dries leaves. and from @GregB's comment it sounds like that's probably the main cause. – J. Musser Jul 13 '14 at 0:58
  • @GregB - if you can get it out of the wind, don't worry about the sun too much - its the wind that's causing this. – Bamboo Jul 13 '14 at 10:24
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    Happy to report, we've moved house and it's back in the land of the living. – Greg B Feb 19 '16 at 14:43
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Yep, that is a Japanese Maple, Acer palmatum

Here's how to plant/grow a Japanese maple tree in a pot:

  • Prep:

  • The preparation necessary before attempting to plant. Make sure all of these steps are done/ready before you begin.

    • Make sure you have a pot large enough to accommodate the plant for at least a year. They will need at least 6 cubic feet (38 US gallons) of potting mix once mature. The pot should have at least one inch's diameter worth of drainage per square foot of container space. More, smaller holes are preferable to one large one. Black pots should be avoided because of heat problems in the sun. Also, trees tend to prefer a shallow rooting, so a pot higher than it is wide will be beneficial.

    • Have the full amount of backfill mix ready before you plant. In a large container, it is useful to have a very free-draining mix. A base of coir (ground coconut husk) is ideal, because of improved fertilizer retention and lower acidity, as compared with peat-based mixtures. There should be at least 5-10 percent drainage helpers, such as coarse sand or perlite.

    • It is best to plant on a day which is overcast, so that the plant will not transipre too fast.

    • If the plant is potted, the roots may have circled the perimeter of the pot. in this case, it is best to score straight down the sides of the root ball in 3-4 evenly spaced places to about 1/2 - 1" deep.

  • Planting:

  • Getting the tree in the pot - here are the basics you need to know.

    • Fill the pot with potting mix , up to the level of where the bottom of the root ball will sit. tamp firmly, to remove air pockets.

    • Place the tree in position in the center of the pot. Fill the rest of the way with potting mix, and tamp again. add more soil if necessary to level it off. Remember that the beginning of the root flare should be visible at all times. Do not bury it. Also, in a container it is not useful to plant high. The top of the potting mix should be level and even.

    • Water well, giving the tree a good soaking. The mix will be a little loose, so don't aim a heavy stream at it. Rather, water with a trickle, and let it soak in.

    • Put some slow release fertilizer on top of the soil, so it can seep into the mix during rain. I've also had success using tree spikes.

  • Care/Maintenance:

  • For the established plant. This is the basic care required for general tree health. This does not cover pest/disease management, which will need to be taken care of case by case.

    • Never water if you can feel moisture when you stick your finger an inch or two into the mix. Overwatering and too much moisture are the biggest reasons I've seen these fail. If the soil is dry finger deep, give it a good soaking, and leave it to dry again. Constant dampness is not what you're looking for.

    • Keep it in at least 6 hours of sunlight for best growth and leaf color.

    • Fertilizing can remain as replacing the extended release fertilizer when it runs out. I usually read the label, to find how long it was designed to last, and reapply about a week before that date is hit.

    • In winter, wrapping the pot in an insulator, and if you're in a very windy location, putting a big box (large enough not to cramp the branches) over the tree will help prevent freeze damage.

    • Pruning isn't usually necessary on these plants, but if you see a dead area, or a branch that is going way out of proportion, some light trimming will be necessary.

    • If the plant becomes root bound, which could take some time, if you can't move it into a larger container, you will have to clean the roots off, and prune them lightly, enough that they will easily spread out in the pot. You can also take this opportunity to replace the potting soil. Do the root pruning and replant as fast as possible, but don't go so fast you do a messy job. Cut back the top to mirror what you did to the roots, taking out only the branges with the worst placement. Try not to suddenly ex[ose a large area of bark, or you may get sun burn.

Your tree has a few issues. First of all, you should repot into a proper potting medium as soon as possible. The soil isn't drying out properly between waterings, and the tree is showing signs of this (it can cause drying around leaf edges, while the plant remains unwilted). Also, the tree has been planted too deep for healthy growth. When you replant, make sure you can see the root flare.

Because of the time of year, you should keep the plant out of full sun for the first couple weeks after replanting. This will keep the tree from over-drying while it regrows some roots.

Your tree looks completely recoverable, it only needs a little proper care.

If you have any questions, or wish for me to expand on something or cover another topic, please let me know.

5

If your pot does not have drainage holes, then it's possible the soil in your pot has become waterlogged and "sour." Adding rocks and sod to the bottom is not enough to provide consistent and proper drainage. Using compost and garden soil in planting pots is also less than optimal, as the structure tends to become either soggy or rock-hard in such a confined area.

The first thing I'd do, is tip the pot on its side and see if water runs out. If it does, water-logging is likely to be your problem. If no water runs out, then you should check the condition of the soil within the pot to see if it has become case-hardened, which prevents water from soaking in as it should. Case hardening often happens when you use garden soil in pots, when the soil ball becomes so hardened and impermeable that water applied to the top of it runs around the root ball instead of soaking in where the roots can get to it.

In any case, at some point you are going to need to either drill holes in your pot, or find another pot of a suitable size that already has them drilled (if your current pot does not have adequate drainage holes already) and then re-pot your tree using some kind of commercial potting mix. If the tree seems to be in dire straits, I'd do it sooner rather than later, and if it was waterlogged, you will also need to trim off any roots that appear to have rotted. If it had a case-hardened soil root ball, then you will need to gently wash the hardened garden soil off of the roots and then replant the tree - again, in a pot with holes using commercial potting mix. In either instance, water the transplanted tree well, and then let it dry out a bit before watering it again. The top inch or so of the soil should feel dry to the touch. Also, keep the tree in a semi-shaded area for a few weeks, to give the roots time to reconnect with the soil and re-establish proper capillary action (the ability to draw water from the spaces within the soil particles into the root system.)

Just to be clear - this is not the best time to be transplanting a small potted tree as a "bare root" and there is a significant risk that the tree may not survive being transplanted this late in the season, but if it's already well on the road to dying, you may have no choice but to risk it. Good luck.

  • I agree about the soil used being the wrong one. – J. Musser Jul 11 '14 at 20:43
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    The pot had a hole in the bottom about and inch and a half diameter. – Greg B Jul 11 '14 at 20:56
  • @GregB Good. Did you put a rock on top? – J. Musser Jul 11 '14 at 20:57
  • @J.Musser I put about 6 or 8 stones in the bottom, they were about the size of my plam but none of them blocked the hole. Water runs out of the bottom of the pot. – Greg B Jul 11 '14 at 21:00
  • Good. It looks like you need to repot and use a better, more easily draining mix. More on the way... – J. Musser Jul 11 '14 at 21:03
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Keep in mind that adding rocks to the bottom of a pot does not improve drainage. Instead, it simply reduces the volume of soil available to the roots, and raises the perched water table. If your objective is to reduce soil volume that's fine, otherwise it could increase the chance of root rot. I know that goes against conventional wisdom, but there's a great writeup of it here: http://forums2.gardenweb.com/forums/load/contain/msg0918361520140.html

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    Pretty large thread. Can you do a quote? By the way rocks can avoid root rot especially in large pots with plates where drained water can be stagnate for days. They may help too with soil aeration. – BYJ Aug 17 '14 at 1:30
  • Andy, from personal experience, if you know what you're doing, rocks of certain kinds will help drainage, not cause a perched table. – J. Musser Aug 17 '14 at 4:35
  • @Andy I agree with you but you need to expand on this answer, not just provide a link – kevinsky Aug 18 '14 at 11:09
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This is a common problem caused by direct sunlight or excessive temperatures. I have a Japanese Maple in my front yard and it gets direct sunlight in the morning. It also goes through similar trauma every summer. I have another plant that is on the side of the house that is shaded and does not get much direct sunlight and it is doing fine.

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