This time of year is usually the time that you will encounter Maple leaf burn. This always occurs first at the very tips of the leaves and these take on parchment colour.
This phenomenon is indicative of a water transport or water storage problem which can be rectified in many ways.
This phenomenon is indicative of a water transport or water storage problem which can be rectified in many ways.
Maples in the ground rarely suffer from leaf burn as they have relatively massive root systems that can reach out beyond their canopy and go deep into the permanently moist soil for their moisture requirements.
Maples in pots are totally reliant on you, me and the weather for their water.
The number one cause of leaf burn is lack of moisture at the roots. Most people who grow maples overlook the obvious fact that a lovely crown of maple leaves is just about the best umbrella there is. So even in a torrential downpour it is relatively easy for a potted Maple to stay dry at it's roots.
This is compounded by the fact that as the tree ages and its rootball uses up the available compost space by growing ever more root there is nowhere for the water to hang about so drought is always a problem that needs to be addressed as soon as it is noticed.
Burnt looking leaf tips are the first sign and you should take action within the first season of noticing the problem.
I do not have a particularly good memory unless it is stimulated with visual signals so to highlight the trees with the problem I tie a bright yellow ribbon around the tree so it frankly looks very stupid and reminds me that this tree needs to be inspected PDQ.
The first thing to do is go out in the pouring rain and look at what happens to the compost when it is raining heavy. If the compost stays dry or just gets a bit damp then the problem lies entirely with the canopy being too dense and the rains runs off outside the confines of the pot.
The solution is to either remove some foliage in the short term or make sure you water the tree daily until you are in a position to repot it into a bigger pot or plant it out in the ground.
If the compost gets wet or even better saturated then the problem lies in either the growing medium or the tree is pot bound and has used up all of the available growing space.
If the tree is pot bound you can sometimes see root tips breaking the surface of the compost looking for room to grow. If the tree is easily manhandled you can knock it out of its pot to see if the root mass is beginning to circle. If it is then re-potting or root pruning is required. I'll discuss both in future but for now you need to establish the cause.
There is as many different types of growing medium as there are Maple varieties and each "expert" or vendor swears blind that theirs is the best. Well most of them are about the same and frankly all the Maple requires is the right mix of air and moisture and the ability to draw on both at the right time. Clearly a badly drained mixture is no good at retaining air and a sandy or compacted mixture is no good at retaining moisture.
There is no "right medium" but what many maples are grown in on the nursery is the worst of all. Peat based mixtures are awful but they are relatively cheap which is why the nurseries use them. They know a proportion of the trees will not survive especially those trees whose owners follow the practice of seeing what the plant is growing in and giving it more of the same but nurserymen are very cost conscious and they do not want to add to production costs by employing a better compost mixture despite its obvious advantages.
So the bad mixture is probably down to someone else. Whatever it is easily solved by repotting into a better mixture at the earliest available time.
So that's it for now.
Get out in the rain. The worst that can happen is you get wet. Don't go out in thunderstorm with an umbrella because the worst that can happen then is that you will meet your maker. But sensible precautions not withstanding if you go and see what goes on with your potted Maples when it rains you will be a much wiser grower than you were when you began reading this article!
Maples in pots are totally reliant on you, me and the weather for their water.
The number one cause of leaf burn is lack of moisture at the roots. Most people who grow maples overlook the obvious fact that a lovely crown of maple leaves is just about the best umbrella there is. So even in a torrential downpour it is relatively easy for a potted Maple to stay dry at it's roots.
This is compounded by the fact that as the tree ages and its rootball uses up the available compost space by growing ever more root there is nowhere for the water to hang about so drought is always a problem that needs to be addressed as soon as it is noticed.
Burnt looking leaf tips are the first sign and you should take action within the first season of noticing the problem.
I do not have a particularly good memory unless it is stimulated with visual signals so to highlight the trees with the problem I tie a bright yellow ribbon around the tree so it frankly looks very stupid and reminds me that this tree needs to be inspected PDQ.
The first thing to do is go out in the pouring rain and look at what happens to the compost when it is raining heavy. If the compost stays dry or just gets a bit damp then the problem lies entirely with the canopy being too dense and the rains runs off outside the confines of the pot.
The solution is to either remove some foliage in the short term or make sure you water the tree daily until you are in a position to repot it into a bigger pot or plant it out in the ground.
If the compost gets wet or even better saturated then the problem lies in either the growing medium or the tree is pot bound and has used up all of the available growing space.
If the tree is pot bound you can sometimes see root tips breaking the surface of the compost looking for room to grow. If the tree is easily manhandled you can knock it out of its pot to see if the root mass is beginning to circle. If it is then re-potting or root pruning is required. I'll discuss both in future but for now you need to establish the cause.
There is as many different types of growing medium as there are Maple varieties and each "expert" or vendor swears blind that theirs is the best. Well most of them are about the same and frankly all the Maple requires is the right mix of air and moisture and the ability to draw on both at the right time. Clearly a badly drained mixture is no good at retaining air and a sandy or compacted mixture is no good at retaining moisture.
There is no "right medium" but what many maples are grown in on the nursery is the worst of all. Peat based mixtures are awful but they are relatively cheap which is why the nurseries use them. They know a proportion of the trees will not survive especially those trees whose owners follow the practice of seeing what the plant is growing in and giving it more of the same but nurserymen are very cost conscious and they do not want to add to production costs by employing a better compost mixture despite its obvious advantages.
So the bad mixture is probably down to someone else. Whatever it is easily solved by repotting into a better mixture at the earliest available time.
So that's it for now.
Get out in the rain. The worst that can happen is you get wet. Don't go out in thunderstorm with an umbrella because the worst that can happen then is that you will meet your maker. But sensible precautions not withstanding if you go and see what goes on with your potted Maples when it rains you will be a much wiser grower than you were when you began reading this article!
Leave a comment