Monthly Q&A - March 2024 | BBC Gardeners World Magazine

Q&A with Ashley Edwards, Humaira Ikram, Christine Walkden and Matt Biggs

Camellias don't need pruning to promote flowering but they can be cut back to improve height and shape after flowering. — Camellias can be cut back after flowering in late spring to improve height and shape

Matt Biggs says: Camellias can easily be hard pruned and reshaped because they are surprisingly robust. Prune back into the older wood after flowering, using a sharp saw, secateurs and loppers to create a basic framework. The strong new shoots that grow from this can reform the bush, or keep future growth more compact by trimming after flowering – they can be grown as a hedge. Your plant will have a large root system so feed with general ericaceous plant food after pruning and keep it well watered using rain water if nature doesn’t oblige. It will take two years before they reflower again.

I have tried growing sweet peas, dahlias and begonias from seed but they all seem to be shooting up without many leaves. Why is that? Anonymous, Yorkshire

Increase the light levels when growing seed to encourage steadier growth — Increase the light levels when growing seedlings to encourage steadier growth

Christine Walkden says: I wonder if the light levels that the seedlings are subjected to are low. This would cause etiolation - stretching of the seedlings towards the light, leading to large gaps between the leaf buds. If you are sowing indoors this can quite commonly occur due to insufficient light, all coming from a single direction. This can be partly remedied by placing a mirror or cardboard covered with silver foil behind the seedlings to reflect any light they are receiving. Ensuring clean glass if sowing under greenhouse situations also will help. The installation of inexpensive LED light may be a way forward if your greenhouse or windowsill does not receive enough light.

March seed sowing with Monty

I have a large mound of recently shredded tree branches. Can I use this now to mulch soft fruits or must they be rotted down first? Nick, Cornwall

It is advisable to allow three months before adding tree cuttings as a mulch — It is advisable to allow at least three months before adding tree chippings as a mulch

Matt Biggs says: You can use fresh material but it removes nitrogen from the soil as it rots down, before releasing it back again once it has fully decomposed. When using fresh material, scatter high-nitrogen feed such as chicken manure around the base of the plant before mulching to compensate for loss of nitrogen from the soil and hasten the decomposition of the woodchips into nutritious compost. Ideally, you should allow at least three months' decomposition before applying chippings as a mulch; at this point tannins in old wood will have washed out. When mulching, leave a 10cm gap around trees and shrubs.

How do I encourage my astrantia to reflower? Aileen, Hampshire

Astrantias can be divided in spring to reinvigorate them before summer

Christine Walkden says: If the astrantia plant is old, it may be running out of steam and in need of dividing. Do this once you can see the plant coming into active growth. Lift the whole clump, remove the old central piece, and just retain the younger, more vigorous pieces from the outside of the clump. These can either be replanted, allowing about 30cm between each small division, or they can be potted and grown on over the summer and then planted out around October. Ensure that the plants are well watered during any dry periods. Feeding with a potash-rich fertiliser applied at the manufacturer’s recommended rate should also help encourage flowering.

10 varieties of astrantia to grow

What can I do to stop things from eating my snowdrop flowers? Barbara, Gloucestershire

Use copper tape around pots to deter slugs and snails

Matt Biggs says: Mice and voles sometimes nibble snowdrop flowers, and the use of humane traps may reduce this. Pheasants and smaller birds may pick at them, so cover plants with chicken wire. Slugs and snails can cause damage to leaves and flowers in milder winters, but they can be deterred by creating slug traps, laying crushed gravel or oyster shell around clumps, using environmentally friendly slug pellets or copper barriers, and slug picking after dark. In late spring when temperatures are above 5ºC, biological control nematodes can be used. Snails usually remain dormant over winter and can be found in clusters in stacks of terracotta pots or in old dry-stone walls – pick over these areas to reduce populations.

How to deter slugs with copper tape

What plants would survive in containers in a full shade, full wind position on my patio? Joanne, Doncaster

Plant Fatsia japonica in spring so it can establish over the warmer months — Plant *Fatsia japonica* in spring so it can establish over the warmer months

Christine Walkden says: It depends on what you mean by 'full shade' and 'full wind'. If it is too dark to read a newspaper without a light source, it will be too dark for most plants. Intense wind is not conducive to good plant growth. Providing some shelter to the plants will help, and this can be achieved by positioning the containers in groups together, so they protect each other. Plants with thick, leathery evergreen foliage should provide some success. Look at some of the beautiful ivies that are now available, hellebores, Pyracantha 'Orange Charmer', Hydrangea macrophylla, Cyclamen hederifolium, Viburnum tinus, Anemone x hybrida 'Honorine Jobert', Liriope muscari, Trillium erectum and Asarum europaeum. Fatsia is now available in variegated forms, which can lift a dark area. Try white flowering bulbs for the spring.

Great spring plants for shade

I want to plant autumn-fruiting raspberries and if possible mix them up with other shrubs or tall plants so that I don’t just have a bed of raspberries. Do you have any suggestions for what I can plant with them that will mean I still have planting to look at even when I have pruned the canes in winter? Rachel, Hertfordshire

Spring bulbs, like muscari, can be a colourful companion to grow alongside raspberries

Matt Biggs says: Raspberries are shallow rooted and naturally spread, so prefer not to have competition from surrounding plants. You can grow them in clumps among ornamentals, particularly autumn-fruiting raspberries, leaving a gap around them and planting herbaceous plants and medium-sized shrubs a distance away, whose branches spread out to fill the gaps but don't grow so tall that they shade the raspberries. Try Euonymus fortunei ‘Emerald Gaiety’, with year-round white-and-green variegated leaves, and small herbaceous plants such as hellebores, hepaticas or erythroniums, which are clump-forming and are easily divided to prevent the roots from encroaching. Small spring bulbs such as muscari, dwarf narcissus and crocus also provide little competition.

I have loose, sandy soil, which I regularly improve with compost. There don't appear to be any worms. Should I be concerned about this? Tony, Dorset

Adding more organic matter is a good way to boost soil health

Christine Walkden says: I suspect that you do have worms if you regularly apply organic matter, as it will be those that are taking it down into the soil. You may well find more worms at the depth were there is more moisture and cooler conditions. Worms will travel to considerable depths in hot weather as the soil temperatures get hotter and start to dry out. If your plants are growing happily, it will not be extremes of pH that are causing issues. I have a similar soil myself and apply heavy applications of organic matter both to my vegetable plot and flower borders, but only see any worms on the occasions that I am digging a deep planting hole for such things as trees and shrubs.

Listen: Creating soil for life - podcast with Arit Anderson

Why is the bark of my cherry tree peeling at the bottom of the trunk of the tree? Karen, Cheshire

Feed cherry trees regularly with a general fertiliser through until the end of March — Cherry trees can suffer from cankers when their bark is damaged

Matt Biggs says: Cherry trees have thin bark, so peeling at the base can be due to damage from a mower or strimmer cable. Take care when working around the tree or, better still, leave a 1m circle of clear soil around the base. This can also be caused by environmental stress due to drought, drought followed by waterlogging or even cold damage from winter frost. Bacterial canker shows as brown spots which fall out leaving holes in the leaves, sunken dead areas on bark which ooze gum and on new growth appearing in spring, or it may not appear at all. Feed with general fertiliser in spring to boost growth.

What can I have in place of a lawn? With eight dogs, four chickens and two ducks I have the odd blade here and there. Do I give up on grass? Hilary, North Somerset

If you can move animals around your garden, this can give a lawn chance to recover. Getty images — If you can move animals around your garden, this gives a lawn time to recover. Getty Images

Christine Walkden says: I think it's very difficult to have a lawn with so many animals. I have a dog and she tears up the lawn every year and in the end I gave up trying to re-seed it, or re-turf it. With so many animals I think you are on a hiding to nowhere, unless you can keep moving them around, giving the turf that is there a chance to recover. I now use fine-grade bark, which works well but is mobile. I'm sorry to say that I have no experience with ducks and they may well eat it! I have seen sawdust used but it is aesthetically not very pleasing.