How can I clean up a border that is over-run with ground elder, couch and bindweed?
In light soils, it may be possible dig out ground elder and couch but the only reliable way is with a weedkiller containing the chemical glyphosate.
I am worried about honey fungus appearing in my garden. What should I do?
If the garden is free from the disease, it is very important to remove stumps of any deciduous trees that you may cut down as it is through the cut surface of stumps that honey fungus invades fresh soil. Either dig out the stump or have it professionally removed with a stump grinder.
Honey fungus affects a wider range of plants (certainly of woody plants) than almost any other, it is very often a killer of the established trees and shrubs that form the framework of a garden, and it is exceedingly difficult to combat satisfactorily. But it must be said that very few gardens are genuinely devastated by the disease and it is usually only a problem in gardens that have once been woodland, an old orchard or have a similar long history of deciduous trees. Many gardeners worry unnecessarily because they believe that almost any garden toadstool is honey fungus. A combination of symptoms is diagnostic: dark, bootlace-like strands in the soil close to the trunk, tawny coloured toadstools, up to 15 cm high, with a somewhat scaly cap up to 15 cm in diameter and with a ring on the stem in late summer and autumn close to the base of the trunk, sheets of white fungal growth with more, but flattened, bootlace strands beneath the loose bark. If a tree or shrub appears to be dying or to have been killed by honey fungus attack, the entire stump should be uprooted and disposed of, preferably by burning, together with as much of the root system as possible. As large a hole as is practicable must then be excavated and the soil dumped in a part of the garden well away from other trees and shrubs - usually, the easiest way to do this is to dig a second hole in, say, the vegetable garden, and swap the soil between the two sites. The hole and surrounding area at the infested site may be drenched with a proprietary honey fungus control solution, which might have some effect in killing the bootlace strands in the soil, although it is unlikely to cure an already diseased tree. The affected site should not be replanted for at least one, and preferably two years, and then with one of the following species that are fairly likely to be resistant: ash, beech, box, clematis, Douglas fir, eleagnus, hawthorn, holly, ivy, larch, laurel, lime, mahonia, robinia, silver firs, sumach, tamarisk, tree of heaven (Ailanthus) or yew.
The twigs on some of my shrubs have developed little pink spots. What causes this?
The cause is coral spot disease which and affects many species of woody plants, although it is rare on conifers. Cut out the affected parts, cutting well into the healthy tissues.
One of the reasons that coral spot is so commonly ignored is that gardeners see it growing on piles of dead woody material (prunings and old pea sticks, for instance) and fail to appreciate that it can attack living tissues also. The coral spot fungus is of the type known technically as a weak parasite - it must first establish itself on dead wood but will spread from there to living parts of the same branch or twig. Stubs of branches left after careless pruning are especially vulnerable as entry points for the infection of the remainder of the plant. The answer is to take great care when pruning not to leave such stubs, and not to leave piles of old woody material lying around the garden on which the fungus can proliferate.
The berries on my pyracantha turn black and drop off before they have matured properly. What causes this?
This is pyracantha scab disease. Spraying with a systemic fungicide in early summer might help but it's sensible to choose Pyracantha varieties like 'Golden Charmer', 'Orange Charmer', 'Sappho Orange', 'Sappho Red' and 'Shawnee' that have some resistance.
The bark of my trees is covered with a greyish leathery growth. What is this and does it do any harm?
The growth is lichen, perhaps with some green algae too. Neither will do any serious harm but lichen can smother trees and shrubs, especially in wet, mild areas.
Algae and lichen will colonise bark and other rough surfaces free from regular disturbance and wherever moisture collects. The simplest way to find a compass direction in a wood is to note on which side of the tree trunks the green growth occurs, for it always colonises the damp, north face. But does no harm to the trees. This is also generally true of the larger, tufted growths of lichen that sometimes clothe the branches and twigs of trees in the really wet, western parts of the country. Nonetheless, when very extensive, these can have something of a smothering effect and are best removed. On deciduous trees, a tar oil winter wash applied during December or January, whilst they are dormant, will kill lichen, although on evergreens, there is no alternative to brushing them off.
There is a large growth in my tree that looks like a bird's nest; is it harmful?
No, merely unsightly. The growths are called witches' brooms.
These growths are very common on certain types of tree and are seen most frequently on birches. They are known as witches' brooms and are caused by parasitic organisms (fungi, bacteria or viruses may all be responsible), but they apparently have little effect on the trees. If they are severely disfiguring, witches' brooms should be cut out and burned although, interestingly, several varieties of dwarf conifer originated as brooms that were cut from the parent tree and deliberately propagated by cuttings and grafts.
How can I control club root on my brassicas?
Most readily by using lime to raise the pH and by raising tour plants individually in pots, and then planting them out with heir roots still in the ball of compost.
Once contaminated with club root, garden soil is likely to remain so, because the causal organism can survive for twenty years or more in the absence of brassicas and cannot be eradicated by treatment with chemicals. If your garden or allotment is free from club root therefore, spare no efforts to ensure that it remains so. Always raise your own plants from seed for transplanting as the disease is usually undetectable at transplanting age and bought plants may have been grown in contaminated soil. By the same token, you should never borrow garden tools from friends whose gardens may contain club root, unless the implements are thoroughly scrubbed in hot soapy water. Nor should you walk from an affected vegetable plot onto your own without similarly scrubbing your boots. If your soil is contaminated, it might be worthwhile installing a proper drainage. Liming will help correct acidity, and you should raiser plants individually in pots.
Why are my onions always soft and mouldy?
If they are spring onions, growing in the garden, the answer is most likely to be white rot disease. If they are stored bulb onions, it is likely to be neck rot disease.
If spring onion foliage turns yellow while the plants are still growing in the garden and, when pulled up, the base of the bulb is soft with a cottony mould growth, then you have onion white rot to contend with. This is a fungal disease and is one of those problems like club root on brassicas, must be lived with rather than eliminated. If you find a few plants in your garden affected for the first time, it may still be possible to prevent the contamination from spreading to the rest of your vegetable plot. Dig out a large spadeful of the soil around the affected plants, taking great care not to spill any as you do so, place it in a large plastic bag and dispose of it away from your garden. If bulb onions appear perfectly sound at the time you pull them from the garden, but subsequently decay during storage and develop a greyish mould around the neck, just below the point at which the leaves emerged, the problem is onion neck rot. The fungus originates on the onion seed and won't persist in the soil but unfortunately, there is no approved chemical treatment for seeds.
Why are my Brussels sprouts always loose and poorly formed?
Probably because they have had too much nitrogen and/or too much water or have not been planted sufficiently firmly. The problem is most likely on older, non-hybrid varieties.
Water is important for a leafy crop such as Brussels sprouts and can sometimes add to the looseness of the sprouts. Water thoroughly at transplanting time therefore, and if you are growing them closely spaced, water throughout the life of the crop. Sprouts grown at the more traditional, wider spacings, however, will thereafter only need additional water in very dry years. Perhaps the commonest reason for Brussels sprouts to form loose buttons is that they are not planted sufficiently firmly. It used to be said that the way to plant Brussels sprouts was to hammer the ground hard and then form a hole with a crow-bar. If a slightly extreme approach, this does, at least, convey the notion that they must be planted very firmly indeed and, on a windy, exposed site and on a light soil especially, should be staked. Incorporate large amounts of organic matter on a light soil too, to help improve its body and if the problem is really severe, grow the shorter varieties such as 'Peer Gynt' or 'Achilles', rather than the taller types which are inherently more prone to becoming top heavy.
Why do my vegetable seedlings shrivel and die?
Most probably because of a common fungal disease which takes several forms, all of which are known collectively as damping-off. Clean compost and seed trays, fresh seed and well prepared soil are the answers.
Most forms of damping-off are caused by microscopic fungi in the soil although a few may be carried on the seeds. Commonly they appear as a small but enlarging patch of dead seedlings in an otherwise healthy box although sometimes the young plants continue to grow in a stunted and feeble manner. On brassicas especially, the form of damping-off known as wire stem is very common; the stem of the young seedlings develops a pinched appearance close to soil level and. in time, becomes wiry in texture. Once damping-off is found in a seed box , the entire boxful should be disposed of for even apparently healthy plants will carry the fungus on their roots and die in due course. Damping-off should be combated by prevention rather than by attempted treatment; always use fresh compost for sowing seeds, always scrub and disinfect seed boxes and pots thoroughly after use and always ensure that the young plants are not placed under unnecessary stress through over watering, inadequate warmth or too little light.
Every year, my apples have black blotches on them and little maggots inside. What causes this?
The black blotches are caused by apple scab disease; the maggots by codling moth but it's difficult to control either successfully in gardens. They don't affect the eating qualities.
Scab is caused by a fungus that largely spends the winter months lying dormant on fallen leaves beneath the trees, although some fungal growth is also present on the twigs. Spores are produced on the leaves and in the twig lesions in Spring and are carried by rain splash and wind to the young foliage which they infect to produce dark brown blotches. More spores are formed there, and these, in turn, infect more leaves and also the young fruits which develop the characteristic crusty or scabby patches. The disease always tends to be worse when there is cool, wet weather around blossom time. I don't believe chemical sprays are worthwhile but collect up and destroy leaves from beneath affected trees, and cut out and destroy scabby twigs in the winter. Codling moth spends the winter on the trees; in a pupae state among the bark crevices. In late spring, the adult insects emerge and the small, dingy females lay their eggs on the leaves and young fruits. The resulting caterpillars burrow into the fruit in a particularly surreptitious manner, usually entering by the eye or close to the stalk so that the entry hole is undetectable. After dining on the inner parts of your apples for a few weeks, the caterpillars re-emerge, crawl down to the bark and pupate until the following season. The only treatment really worthwhile is to install a codling moth trap in the trees.
Why have the leaves on my peach tree curled up and turned red?
Because of a disease called peach leaf curl. It is very prevalent in wet areas or wet seasons and is almost impossible to control.
Peach leaf curl is always most severe in seasons following a cold, wet spring for these provide just the right conditions for the leaf curl fungus to infect. It survives the winter within cracks in the bark and on the leaf buds, from where it emerges to infect the young leaves as they unfold. This infection causes the characteristic puckering that gives the problem its name and later, as the fungus grows within the leaf tissues, a reddening develops and a white powdery 'bloom' forms. This powder is a mass of fungus spores which subsequently are blown to the twigs where they germinate in preparation for the winter once more. No chemicals are really effective and if you enjoy growing this type of fruit, my advice is to try apricots instead as they are rarely affected.
Why do the leaves of my plum tree have a silvery shine?
Probably because it has a disease called silver leaf. This is especially common on ' Victoria ' and can't be controlled.
If there are obvious signs of branch death, you will be able to determine the cause more precisely. Saw off any dead branches and look carefully at the wood within. If there is no obvious discolouration, then the problem may simply be a condition known as false silver leaf; an indication that the tree is short of water and/or fertiliser. If the wood displays dark staining, however, you have genuine silver leaf to contend with and the causal fungus may make its presence apparent later in the year when dark purple bracket-shaped or crusty bodies appear on the bark. There is no chemical answer to silver leaf and the best policy is simply to wait and see what happens after any dead branches have been cut off and destroyed. Quite commonly, affected trees recover naturally. Nonetheless, if the symptoms spread, and especially if the silvery effect appears on any suckers, then entire root system is diseased. In these circumstances, the tree should be felled, as much as possible of the root system dug up and burned. The presence of silver leaf spores in the air in the autumn is why plums shouldn't be pruned until the spring.
Why do the leaves of my raspberries have yellow stripes?
Possibly because of virus but much more likely because they are on a chalky soil
More than most garden plants, raspberries suffer from an inability to take up the element iron from alkaline soils; and iron is essential for chlorophyll to be manufactured. When plants do suffer in this way, their overall efficiency is impaired because a lack of chlorophyll means a lack of the ability to build nutrients from carbon dioxide and water, the process known as photosynthesis. Fortunately, the problem is fairly easily remedied. Apply sequestered iron (iron in a form that plants can take up, even in chalky conditions) at the start of each season
My tomatoes have big black blotches on them. What is the cause of this?
It is a problem called blossom end rot, caused by a shortage of calcium but exacerbated by a shortage of water. Some varieties are particularly prone to this.
Blossom end rot is not, strictly speaking a rot because there is no decay of the tissues. A clue to the cause of the problem is its greatest prevalence in hot, dry summers for tomatoes that have experienced even a short period of water shortage will almost always develop some blossom end rot symptoms. The water shortage is not the direct cause but indirectly it gives rise to a deficiency in the fruit of the element calcium. Most composts used for tomatoes do contain sufficient calcium for plant growth but it is most important that the plants are not placed under stress as this renders the calcium unavailable to them. It is essential therefore, to ensure that the plants' roots are never allowed to dry out.
Do you have a genuinely effective control for slugs?
Traditional slug control methods such as baited traps containing beer can often be and effective as anything. If you aren't averse to using chemical controls, slug pellets are reliable and safe to other creatures if use as the manufacturers direct.
Moist soils with high organic content support large populations of slugs and if conditions in a garden are particularly favourable it may be impossible to prevent damage to plants. Some relief is given by cultivating frequently and thoroughly to expose eggs, young and adult slugs to predators and weather; by limiting use of organic fertilisers, such as manures and composts; by restricting use of mulches around plants and by generally maintaining good garden hygiene. In addition, slugs may be trapped by laying old lettuce or cabbage leaves, grapefruit skins, old sacking, bran and various other materials on soil surfaces. Warm humid evenings give best catches. Inspect traps early next morning and kill slugs by dropping into a bucket containing a strong solution of salt or very hot water. Slugs can also be trapped by sinking shallow dishes to soil level and filling them with beer, which attracts them, intoxicates them and drowns them. Proprietary traps serve the same purpose. Beer remains effective for 2–3 nights. Alternatively, use poison baits containing either metaldehyde or methiocarb. These are sold as slug pellets which are placed in strategic positions near susceptible plants. Pellets remain effective for 3–4 days and repeat applications may be necessary. Methiocarb pellets are expensive but generally give best results and 1 kg of pellets should be sufficient to treat about 1 hectare. Follow manufacturer's instructions for use carefully. Keep children and pets away from treated areas and do not use edible crops until at least a fortnight after treatment. Areas where celery or potatoes are to be grown are best treated before planting to reduce the local slug population so far as possible. Susceptible potato cultivars, especially ‘Redskin', ‘Maris Piper', ‘Desiree', ‘Glade', ‘King Edward', ‘Record' and ‘Pentland Crown' should not be grown where slugs are troublesome and main-crop potatoes should be lifted and stored as soon as possible, not left in the soil at the end of the growing season. Protect seedlings of ornamental plants and vegetables growing in seed trays or in the open ground by sprinkling slug pellets, weathered ashes or soot around them and use the same treatment to protect the young growing points of susceptible plants in the spring. Snails are generally less troublesome than slugs. Where they are pests they can be dealt with in the same way and it is also possible to pick them off plants by hand.
How can I control ants?
Use plenty of organic matter on dry, well-drained soils and proprietary ant baits or other chemical controls in other places.
Ants are generally most active in dry, light soils where they can tunnel and incorporating plenty of moist organic matter will be beneficial. Direct treatment of nests is the best method of control as it eradicates ants at source. If nests are accessible, treat them by watering a spray-strength solution of proprietary chemical ant control into the entrances using sufficient solution to permeate the whole nest. If nests are inaccessible they may be poisoned indirectly by putting down baits or dusts in areas where workers are active. Proprietary ant baits usually consist of sugar or other attractants mixed with a persistent insecticide. These are applied to the soil or are placed in shallow lids or other containers to which ants have easy access. Workers then carry particles of poisoned bait back to the nest. Baits should be renewed regularly so long as ants continue to visit them and it may take weeks of baiting before there is any marked reduction of ant populations.
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