Looking through all the information I have on mycorrhiza, to put in this post or spread it over several days would produce an impossibly long article. For the moment, the best introduction I can give is to send you to the following site: Introduction to Mycorrhizas
I'll discuss how best to manage mycorrhiza in the garden tomorrow and provide some information for growers of exhibition vegetables.
Tuesday, November 6, 2007
Friday, November 2, 2007
What not to buy
Following on from yesterday's post, I thought it would be a good idea to illustrate some typical aphid activity. If you click on the picture, I've put two larger versions on my web site. You'll notice they're starting to congregate at the base of the dying leaf stems and around the base of the current season's shoots. These are all ideal hiding places to lay eggs; not to get away from you but to protect the eggs from birds. Again, the same advice as yesterday; kill them before they kill your plant! And yes, small plants can be severely weakened in the spring and can die.When I'm browsing on the Internet I sometimes suffer from WILF (what was I looking for!) and I ended up on a Technorati page listing that had links to some Youtube videos. I clicked on one of them and it turned out to be a clip from Garden Time tv and an interview and product plug with a garden centre owner describing some Japanese maples. So far, so good, although I never take any notice of people telling me a particular variety is only going to get to a specific height; a good rule of thumb: take the height and double it!
What they were advertising at the end illustrated the danger of jumping on a bandwagon without having the facts to back it up. In essence, they were promoting mycorrhiza as a 'must have' for improving the quality of your Japanese maple. The product contained lots of different strains that would, apparently, all help to make your maple healthier and more vigorous, protect it from soil-borne diseases and generally act as a universal panacea.
The reality, however, is somewhat different. Mycorrhiza have little or no effect on the well-being of your Japanese maple and applying beneficial fungi to them will not be cost effective.
As a professional nurseryman, I started using mycorrhiza in the late nineties when reliable strains first became available, although having said that, there was a lot of rubbish about just as there still is and considerable testing of their effectiveness had to be done. Initially, it held some promise, at least in theory and I started using it extensively but more research and field trials showed that, on it's own, it was doing nothing. There were other elements of the soil microflora that had a far more important role as far as Japanese maples were concerned; specifically, bacteria and some of the most important of these are Azotobacter, Pseudomonas and Rhyzobium.
The subject of soil microflora is an important one, not just for Japanese maples but for most garden plants. I'll come back to this subject next week as there is a large amount of information that can be of great benefit to all gardeners and I'll also have a secret tip for growers of exhibition vegetables that probably no one, outside of a laboratory, is aware of.
Need more information? find it at growing Japanese maples.
Thursday, November 1, 2007
Japanese maple pests
Today I took my first inspection through my stock plants to see what wood is going to be available for grafting this winter and was glad I hadn't left it any longer. Although I regularly inspect plants during the summer when aphid populations can build up quite quickly, some had obviously been overlooked. Several trees had infestations of juvenile aphids crawling all over them and action need to be taken fast.
To the casual observer, the sight of aphids in the autumn, whilst acting as a reminder that they need to be removed, won't engender any sense of urgency. It's a job that can be done when you've got some spare time next week or next month, if at all. You're thinking 'the only thing they seem to be doing is putting a sticky deposit on the leaves; they're going to fall off shortly and the upcoming cold weather will kill the aphids off so I'll leave it as I've got more important things to do in the garden'. Big Mistake!
What you can't see unless you get up very close and if you can see, it's too late, is the aphids are laying eggs. Initially, they're walking up and down leaf stalks and shoots, but gradually they will start congregating in specific ares, ready to unleash a time-bomb next spring. They will start laying their eggs in the leaf axils where next year's buds are developing. They're going to be in tiny cracks in the bark next to the buds and in the bud sheaths themselves. Once they've been laid, there is nothing you can do apart from wait for them to hatch next spring.
Unfortunately, next spring is going to be too late to minimise the extensive damage they can cause as, conveniently for them, they hatch just as the buds start expanding. But this time they're not going to be walking all over the leaf surface, at least not initially; they're going to be within the expanding buds. But it gets worse! They're not interested in the fully opened leaves where it's easy to get at them; they're going to be feasting om the most succulent part of the shoot, the growing tip and all you'll see is a mass of sticky distorted shoot tips covering the whole of your Japanese maple and severely weakening the growth of your plant.
When it gets to this stage, control is very difficult without causing extensive damage to the shoots. Repeated applications, because they won't go without putting up a fight, with garden chemicals can do almost as much damage as the aphids themselves. By spraying now with something like a soap solution or Neem oil, that works by suffocating them, you can quickly eliminate future problems. So today's tip is check for aphids, not just on your Japanese maples, but on all your trees and shrubs. That way you won't have any unpleasant surprises next spring!
Need more information? Get it at growing japanese maples.
To the casual observer, the sight of aphids in the autumn, whilst acting as a reminder that they need to be removed, won't engender any sense of urgency. It's a job that can be done when you've got some spare time next week or next month, if at all. You're thinking 'the only thing they seem to be doing is putting a sticky deposit on the leaves; they're going to fall off shortly and the upcoming cold weather will kill the aphids off so I'll leave it as I've got more important things to do in the garden'. Big Mistake!
What you can't see unless you get up very close and if you can see, it's too late, is the aphids are laying eggs. Initially, they're walking up and down leaf stalks and shoots, but gradually they will start congregating in specific ares, ready to unleash a time-bomb next spring. They will start laying their eggs in the leaf axils where next year's buds are developing. They're going to be in tiny cracks in the bark next to the buds and in the bud sheaths themselves. Once they've been laid, there is nothing you can do apart from wait for them to hatch next spring.
Unfortunately, next spring is going to be too late to minimise the extensive damage they can cause as, conveniently for them, they hatch just as the buds start expanding. But this time they're not going to be walking all over the leaf surface, at least not initially; they're going to be within the expanding buds. But it gets worse! They're not interested in the fully opened leaves where it's easy to get at them; they're going to be feasting om the most succulent part of the shoot, the growing tip and all you'll see is a mass of sticky distorted shoot tips covering the whole of your Japanese maple and severely weakening the growth of your plant.
When it gets to this stage, control is very difficult without causing extensive damage to the shoots. Repeated applications, because they won't go without putting up a fight, with garden chemicals can do almost as much damage as the aphids themselves. By spraying now with something like a soap solution or Neem oil, that works by suffocating them, you can quickly eliminate future problems. So today's tip is check for aphids, not just on your Japanese maples, but on all your trees and shrubs. That way you won't have any unpleasant surprises next spring!
Need more information? Get it at growing japanese maples.
Wednesday, October 31, 2007
Suitable soil types for Japanese maples
One of the many comments I get from visitors to my stand when I'm exhibiting at flower shows is 'I cant grow Japanese maples on my soil' and it seems to be a common fallacy that they need an acid soil. The reasoning behind the assumption is they've grown a maple before and it's died and they garden on chalk, lime or clay soils; therefore it's the fault of the soil.
The maple family in general and Japanese maples in particular will tolerate any type of soil and are quite happy with a pH that ranges from 4.5 to 7.5. The lower limit will be when growing in pure peat without any added lime to counteract the acidity, right up to very alkaline soils based on chalk. The common denominator of all so-called problem soils is not the pH but rather their inability to hold moisture during the summer.
The only overriding requirement as far as soil types is concerned is that it is reasonably free-draining. Maples dislike having their roots in waterlogged soils, especially during the winter months when there is no root activity to reduce moisture levels and the root system runs the risk of being suffocated through lack of air movement. The end result of that scenario is the roots will rot and allow infection to spread through the plant.
To combat the problem of specific soil types not holding sufficient moisture in the summer, we come back to the need to mulch. This overcomes the perceived problem of growing Japanese maples in soils that, at first glance, seem inhospitable to their needs.
Waterlogging in winter is often the cause of Japanese maples coming out in leaf in the spring, putting on a good display of foliage and then suddenly dying, often coinciding with strong winds or a slight frost. These events are then blamed for the demise of the plant whereas the real culprit has been waterlogging and moisture stress. The tree still has some reserves of energy left in what remains of the roots and also in the body of the tree, which is why new growth starts out with such promise. Unfortunately, with little or no back-up it can't sustain that growth and the result is sudden death. Mulch to prevent stress in the summer and pick an area in your garden that has reasonable drainage and you remove at a stroke the main reason maples die.
Although frost can cause some damage in early spring just as the leaves are coming out, a healthy plant will continue to put out new growth and damaged leaves will have no long term affect. There is, in fact, an easy way to differentiate between frost damage and root damage. If the tips of the shoots are blackened or burnt but the shoot is still generally firm, it's frost. If the shoots droop and there is no firmness in them at all, then the damage is in the root system and the plant is going to die or is already dead. There are ways to rescue them and Ill cover some methods that could potentially help in a later post, but before your Japanese maple is completely dead!
Need more information? Get it at growing Japanese maples.
The maple family in general and Japanese maples in particular will tolerate any type of soil and are quite happy with a pH that ranges from 4.5 to 7.5. The lower limit will be when growing in pure peat without any added lime to counteract the acidity, right up to very alkaline soils based on chalk. The common denominator of all so-called problem soils is not the pH but rather their inability to hold moisture during the summer.
The only overriding requirement as far as soil types is concerned is that it is reasonably free-draining. Maples dislike having their roots in waterlogged soils, especially during the winter months when there is no root activity to reduce moisture levels and the root system runs the risk of being suffocated through lack of air movement. The end result of that scenario is the roots will rot and allow infection to spread through the plant.
To combat the problem of specific soil types not holding sufficient moisture in the summer, we come back to the need to mulch. This overcomes the perceived problem of growing Japanese maples in soils that, at first glance, seem inhospitable to their needs.
Waterlogging in winter is often the cause of Japanese maples coming out in leaf in the spring, putting on a good display of foliage and then suddenly dying, often coinciding with strong winds or a slight frost. These events are then blamed for the demise of the plant whereas the real culprit has been waterlogging and moisture stress. The tree still has some reserves of energy left in what remains of the roots and also in the body of the tree, which is why new growth starts out with such promise. Unfortunately, with little or no back-up it can't sustain that growth and the result is sudden death. Mulch to prevent stress in the summer and pick an area in your garden that has reasonable drainage and you remove at a stroke the main reason maples die.
Although frost can cause some damage in early spring just as the leaves are coming out, a healthy plant will continue to put out new growth and damaged leaves will have no long term affect. There is, in fact, an easy way to differentiate between frost damage and root damage. If the tips of the shoots are blackened or burnt but the shoot is still generally firm, it's frost. If the shoots droop and there is no firmness in them at all, then the damage is in the root system and the plant is going to die or is already dead. There are ways to rescue them and Ill cover some methods that could potentially help in a later post, but before your Japanese maple is completely dead!
Need more information? Get it at growing Japanese maples.
Tuesday, October 30, 2007
Death by watering Part 2
As promised, here are some photos of Japanese maple seedlings growing in an extremely dry environment. The pictures are quite small so I've put a link to a page on my web site where you can see bigger images; just click on the first picture. The first picture shows a general view of the tunnel that was used to grow understock; you'll notice that all the plants are red maples; the reason being that if the graft fails I still have a atropurpureum seedling to sell as they are always more popular than green forms. Even the experts such as myself(!) are not infallible! These photos were taken in April and the plants have just come into growth. The overhead irrigation lines were dis-connected when the crop, of which these seedlings were part of, was lifted thirty months prior to these pictures being taken.
The second picture shows the seedling in the centre of the tunnel whilst the last picture shows plants near the side of the tunnel. Notice that they are slightly larger due to condensation running down the inside of the film as indicated by the presence of moss next to the film. Also, because they are at the edge of the tunnel, they are the first to get the benefit of any deep moisture that migrates through the soil. The film is buried in a trench fifteen inches deep but moisture will still creep in as nature abhors an imbalance. Shade temperatures in the summer get up to 100 deg.F and the soil in the tunnel would have been bone dry but there would always be a small but constant supply of moisture at about two feet or possibly lower with the tunnel cover acting as a mulch to prevent fluctuations in moisture levels. Even in that environment, if I'd put a sheet of polythene on the ground, the soil would have been damp right up to the surface!
I hope that I've succeeded in showing you that watering a Japanese maple once it's been planted can be a dangerous exercise and that they are better left well alone. As water becomes increasingly scarce and expensive, particularly if your local utility has decided to ration it or impose a hosepipe ban, it is far better to let your maple fend for itself; they're much more intelligent than us when it comes to knowing what it's needs are as they've been doing it for a very long time!
Of course, all the above pre-supposes that you have a healthy plant waiting to be transplanted. The reality is likely to be somewhat different as most purchased plants exhibit some degree of poor health and may well need a period of convalescence before they're ready to go out into the big, wide world. This is another subject in need of a visit and I shall go into it in some detail in the near future.
Need more information? Get it at growing Japanese maples.
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