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Ask John Negus
from Bvhhh
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JOHN NEGUS
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Autumn is a good time to move most shrubs and trees, including witch hazel
When should I move a witch hazel?
QI planted a witch hazel in February this year. I now believe that I planted it too close to the fence and I need to move it forward by 3ft (90cm) or so. Can I move it now or should I leave it until spring, after it has flowered?
Steve smith (via email)
ANow, or in November, is the best time to relocate your Hamamelis x intermedia ‘Arnold Promise’. The soil is still ‘summer warm’ and your charge will re-establish before temperatures plummet in winter.
Start by digging a trench around the tree, about 18in (45cm) from the trunk, to expose the roots. Cut through large roots, but leave fibrous roots intact. Ultimately, unearth the entire root system. Then, pivoting the rootball to one side, then the other, enclose it in heavy-gage plastic to stop it from drying out. Next, dig a hole the same depth as the rootball and twice as wide. ‘Implant’ the rootball so that it’s at the same depth as before.
Incidentally, you may need another person to help you move the tree. If you do, secure a pole to the trunk so that both of you can lift it. Finish by watering liberally to ensure that roots are in close contact with the soil.
Phycomyces nitens often colonises bird droppings
Unusual fungus
QThis strange plant is growing under the bird feeders where seed has fallen. What is it?
Maureen Watson (via email)
AThe curious fungus in question is a primitive species called Phycomyces nitens. The name alludes to its hair-like structure.
Usually seen colonising dog and other animal faeces, it is probably growing on bird excrement.
It is not harmful and doesn’t infect plants. I suggest that you remove it and compost it.
Groundbugs are plentiful in the UK and don’t harm plants
Why have my potted hollies died?
QCan you please tell me why my two holly bushes growing in ceramic pots have suddenly died?
Jean Breen (via email)
AI am sorry that your hollies, which were planted in ceramic pots last year, have died. There are many reasons for a plant expiring: drought, waterlogging, vine weevil attack and disease being among them.
I am wondering about the size of pots chosen and whether there are adequate drainage holes. If there are, did you cover them with crocks or pea shingle to ensure that they have not become clogged?
Vine weevil larvae chew and kill roots. I suggest that you ease your
Waterlogging and pests can kill potted holly trees
plants from their containers and carefully examine their root systems. If you see small creamy grubs with brown heads, they are vine weevil larvae and may be the culprits.
What are the bugs?
QMy garden has been invaded by these small insects. Do you know what they are and if they do any harm?
Sandra Baxter, Lincolnshire
AThe creatures appear to be a kind of groundbug. There are 91 species in Britain and Ireland, and they are seldom harmful to plants.
Yours could be a colony of European chinch bug (Ischnodemus sabuleti). As it’s rarely seen, I urge you to refrain from controlling it with a pesticide as it will feed other creatures.
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JOHN NEGUS
Wildlife-friendly ways to beat the slugs
Beer traps and wool pellets are safe ways of preventing slug and snail damage
Quick questions & answers
QI have planted a persicaria under my magnolia where it is now in flower, but someone told me it’s a weed. Should I keep it?
Margaret Pagett (via email)
QOur garden is on the west coast of Scotland and we have a problem with slugs and snails. We don’t want to use chemicals, so what are the best wildlife-friendly deterrents?
Audrey Maceachen (via email)
AThere are several substances to deal with slugs and snails that won’t harm garden wildlife, but will help keep plants safe. I urge you to control them using beer traps, nematodes, garlic, sheep’s wool, prickly leaves and growing plants that slugs abhor: Nematodes: Also called eelworms, they are microscopic creatures inoculated with a toxin that kills slugs. Nemaslug is the trade name for this remedy. Ideally, apply it every six weeks with a watering can fitted with a coarse rose. Slug tape: Made from copper, it encircles pots and other containers. Slugs hate crossing it. Serrated copper snail tape, flexible tape, copper rings and copper bands also halt their progress. Slug Gone wool pellets and wool matting are also effective in keeping the slimy brigade at bay. All three products are available from Green Gardener: & 01493 750061, 8 greengardener.co.uk. Also try: Garlic spray: Choose from several internet recipes. Prickly leaves: Mature and hard holly leaves keep molluscs from softstemmed plants, as do slate chippings. Woolly leaved plants: Plants such as nepeta are normally shunned by slugs. Beer traps: Fill a plastic carton with beer and place it in the soil with the lip just above ground level. Slugs and snails fall in and drown but beneficial beasties such as ground beetles are kept safe by the raised lip.
When will our pears finally ripen?
QI have a great crop of large pears, although I don’t know the name. They are rock hard, but unless I pick them the blackbirds will have them all. How do I ripen them?
Perpetua McArdle (via email)
Some pears stay hard and unripe for several months
AI am sorry that birds are devouring your ‘rock-hard’ pears before they have ripened. The best way to protect them from birds and help them mature and develop full flavour is to enclose each fruit in a greaseproof bag.
It’s a tedious job, but worth it. Check fruits periodically to check how soft they are becoming. When they yield to light pressure, harvest them and fully ripen them off indoors in a cool place.
Unfortunately, some pear varieties are not ready for eating until late in the season or even into the New Year. A There are many species and varieties of persicaria that are ideal for colonising and enriching sunny and shady, wet and dry parts of the garden. Most quest freely and have to be kept in check.
QI wondered what this was on a leaf so took a photo. Any idea?
Maggie Stephens (via email)
AThis is a harlequin ladybird pupa. Though adults prey upon our native species of ladybird, they also consume aphids and other tiny pests so they are not ‘enemies’ in the truest sense of the word.
QOur roses were eaten by what looked like caterpillars. Will they survive?
Bob Seymour (via email)
AThey could be rose sawfly caterpillars but your roses won’t be irreversibly damaged and will produce new foliage in spring.
Rowan trees can be cut back and pollarded, and it won’t ruin their shape
Contact John Negus by email address below Email: amateurgardening@futurenet.com
Bulbs are hardy and early shoots will survive
Should we prune our mountain ash?
QWe have a ‘Joseph Rock’ mountain ash tree that needs pruning, but I’m concerned that if we cut too much off it will lose its elegant shape. What would you advise?
Roz Bareham, Salisbury, Wiltshire
AMountain ash, also known as rowan, can be cut back every few years. We have one, too, and I effectively pollard it, cutting each of the branches back to 1-2in (2.5-5cm) of its point of origin.
The new growth retains the tendency to grow upwards as straight stems, which can only be induced to branch by cutting their tips out – and even then the branching is very insignificant and just grows upright!
So if you did feel you needed to prune it I don’t think you would need to worry about losing the shape. If you simply wanted to bring the height down a bit you could cut the tips out of each branch.
An alternative would be to remove one or two branches down to within 1-2in (2.5-5cm) of their point of origin, and if you were to do this to different branches every year you could probably keep the tree at a smaller height.
You may also need to remove suckers appearing from the base of the trunk.
How to propagate begonias from seed
QHow do I propagate begonia seeds? I have a heated propagator.
Judith Haigh (via email)
AI suggest that you sow your begonia seeds in February, germinating them in a heated propagator at a temperature of around 19ºC/66ºF.
Mix seeds with fine sand and sprinkle them onto the surface of a pot or seed tray filled with seed compost, to which you have added, by volume, a quarter part perlite for extra drainage. Carefully Begonia seeds should be sown in February water them in.
When seedlings are about 1/2in (13mm) high, prick them out 2in (5cm) apart and grow them on in good light and warmth. Set them outdoors in a border, bed, patio pot or hanging basket when frosts finish in early June.
Fears for shoots
QI planted lots of spring bulbs recently (iris, muscari, crocus, daffodils and alliums) and some of them have started sprouting. What should I do?
Katie French (via email)
AIt’s good to hear that you’ve planted irises, muscari, crocuses, daffodils and alliums to cheer spring. They’ve appeared earlier than usual because it has been unseasonably mild.
If it turns very cold and frosty, and new leaves are well developed, protect them with fleece.
Pleasingly, most spring-flowering bulbs are resilient to dramatic changes in the weather and are rarely harmed by a sudden drop in temperature.
QHow do I overwinter my calla lilies? I have grown them successfully for the first time and I have no idea what to do with them now.
Winter calla care
Andrea Hook (via email)
AAssuming that your calla lily is growing in a container and is still relatively young, overwinter it in an unheated greenhouse, transferring it to a warm, sunny spot outdoors when the risk of frosts has passed. If you don’t have a greenhouse, cover the crown – basal buds and lower parts of leaves – with a 4in (10cm) layer of chipped bark to insulate roots from frost. Also, wrap the pot in bubble plastic to stop compost from freezing.
Overwinter calla lilies in a frost-free greenhouse
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JOHN NEGUS
When can I plant perennials? Looking after aloes
Banana advice
QWe have moved to a new house and want to add some perennials and lilies to the garden. Is autumn a good time to do so?
Bob and Marie Hill, Faversham, Kent
Future
AThe best time to plant shrubs and perennials depends on the weather conditions and soil structure of your garden. If early frosts and prolonged spells of freezing weather are likely, or if your soil is heavy and prone to waterlogging, then you are probably wise to leave planting until spring.
However, although we are coming to the time when top growth is slowing towards winter dormancy, root growth often continues well into December. The advantage of planting now is that plants still have six or eight weeks of root growth available when they can start to make themselves at home in their new surroundings, and this will be really beneficial when they come back into growth in the spring.
Lilies are best planted in autumn. Ideal conditions are a south-facing, slightly sloping site in sun or partial shade. Any ordinary garden soil should be fine, but some lilies prefer alkaline soil and others struggle where there is lime in the soil.
Lilies benefit if their soil is enriched with leafmould or well-rotted compost. Heavy clay soils should have coarse grit worked into the planting area.
If the soil is particularly wet or prone to sitting wet, then it might be worth mixing grit into the soil for back-filling as well as into the base of the hole to aid drainage. Alternatively, you could back-fill the hole with a lighter mix of multi-purpose compost and soil to improve the conditions immediately around the bulb.
Future Perennials can be planted in autumn, and lilies can be grown in pots if your soil is heavy clay Q Is this a type of aloe vera and, if so, how do we care for it?
Andrew Coxhead, Warminster, Wiltshire
Aloe veras are not A The mystery plant appears to fully hardy and need winter shelter be an aloe and, in common with other aloes, it is not frost hardy.
I suggest, therefore, that unless you have a very sheltered, sunny garden, virtually free from frost, you overwinter it in, ideally, a heated greenhouse.
If it’s unheated, erect a framework of canes over it and drape them with several layers of fibre fleece when temperatures plummet.
Insulate potted bananas with fleece before winter
What is this unusual plant?
QPlease could you identify this plant that grew from a wild seed mixture?
Marian Kloet (via email)
AThe mystery plant appears to be Amaranthus cruentus. A native of South and North America, where it has existed for at least 4,000 years, it’s an annual whose nutritious seeds are feasted upon by a wide range of birds and other animals.
Unfortunately, it is not hardy in the UK and, if you wished to grow it again, you would have to sow it in a heated greenhouse in March and transplant it to a bed or border when frosts finish.
Alternatively, consign seeds to a prepared sunny patch in mid-May, or as soon as night temperatures are well above zero.
Amaranthus cruentus is an annual that produces edible seeds Q How do I look after my potted Musa basjoo banana plant in winter?
Sarah Howe (via email)
ACut away the leaves of your banana plant so you’re left with the trunk, then wrap the pot in bubble insulation and/or horticultural fleece. Mulch the surface of the pot with well-rotted manure or an insulating layer of straw.
However, make sure you can still water your plant during very dry spells because bananas have fleshy roots and it may take time for the plant to get going again in spring if they dry out.
Then stand the plant on feet and set it somewhere sheltered outside or in a greenhouse.
