Gardeners’ Question Time

Q GQT Gardeners’ Question Time Our experts tackle your gardening problems, including hungry badgers, a dingy veg patch and some very wobbly dahlias Bob Christine Matt Flowerdew Walkden Biggs

Bob is an organic gardener and has designed his garden to produce lots of veg, fruit and cut fowers. Garden writer Christine appears on BBC1’s The One Show. She is also a lecturer and tour leader. Matt trained at Kew and has been gardening professionally for more than 30 years.

Q Help! My veg patch is shady and full of snails

Jess, London

ACHRISTINE SAYS I would not give up on the vegetables, despite the shade and snails.

Leaf vegetables such as lettuce, cabbages, Brussels sprouts and salad crops do reasonably well in this situation. Is it possible to prune the trees a bit to reduce the shade that they cast, by lifting or thinning the canopy?

Control the snails by going out at night and physically removing and then disposing of them. Beer traps are said to work, but I have never found them that good at reducing the snail population. Slugs, yes, but not snails.

Growing your plants in pots or modules first, so they are a reasonable size before planting them out, may also result in more success than sowing direct.

Careful, sparing use of slug pellets based on ferric phosphate may also work as a last resort. Read the instructions – do not over-apply, and make sure they are stored safely.

Q&A TEAM ANSWER Shaded veg patches

Module-sown crops have more chance against slugs and snails

AMATT SAYS Many different vegetables will grow quite happily in a degree of shade.

Try beetroot, carrots, chard, kale, kohlrabi, runner beans, spinach, peas, lettuce, radicchio and oriental vegetables.

Sowing seeds in modules or pots on the windowsill, and then transplanting them, will give the plants a good start.

Herbs for part-shade include chives, coriander, sweet cicely and mint. Plant mint in a large pot, then plunge the pot into the ground with the rim just above the surface, to reduce the plants’ ability to spread. Mint needs re-potting every one or two years.

Fruit that grows in some shade includes rhubarb, redcurrants, raspberries, gooseberries and blackcurrants. Make sure your crops are well watered after planting out. This is a great opportunity to experiment.

Q My parsnips are weird: is powdery mildew to blame?

Leanne Coleman, by email A BOB SAYS Parsnips exhibit both downy and powdery mildew, neither of which is serious, or is this problem. They can also in rare instances suffer some from diseases of carrots such as violet root rot – which this is not, either.

I think your parsnips have canker, which is a symptom of a fungal infection rather than a specific disease itself. Even cankerresistant varieties of parsnip may develop some lesions – although yours are not the usual dark colour.

There are various factors that make canker more likely to occur in a parsnip crop, such as drought, over-rich soil, water lodging in the crown and damage to the root from tools. Liming, or dressing the soil with wood ashes, will help protect parsnip sowings against this problem in the future.

Parsnips mature slowly, so have lots of time to pick up problems

Green manures can improve soil after hungry crops like potatoes

Q Why is my phacelia okay after potatoes, but not after onions?

Brian Hilton, by email

ABOB SAYS This could be an interesting observation of a ‘companion’ effect; many plants will exude fluids into the soil that prevent seeds from germinating, and others that alter soil life activity to suit themselves.

However, it’s also likely that the loosened soil following spuds was easier for the seeds to grow in than the hard bed left after onions.

Astrantias prefer the partial shade of a nearby tree or shrub

Q I saw this plant at Chatsworth. Can you tell me what it is?

Sandy Dobbie, Cornwall

ACHRISTINE SAYS This is astrantia, a herbaceous perennial. It’s often grown in some shade, but a sunny, moist spot is ok. It likes moisture-retentive, rich soil, and may need watering in dry spells.

You can buy it in various colours and it makes an excellent cut flower, with distinctive bracteoles surrounding whorls of tiny flowers.

Q My peas grow poorly, but my beans grow very strongly. Why would this be?

B Jandu, by email

ACHRISTINE SAYS The initial germination and growth of directsown peas is greatly influenced by soil moisture.

Once a pea starts to germinate, if it becomes dry again the new growth will often shrivel up below the soil surface before it can be seen. To get your peas to establish strongly you need to water them thoroughly and regularly.

Once they are growing away they do not require a lot of water until they start to flower. They should receive a good soaking once a week while they are in flower and when the pods are swelling. Mulching around the plants helps, too.

Mice can also eat the seeds. One way to avoid this is to sow your peas into pots and then to plant them out once they have reached a suitable size.

The hot, dry early summer was hard for June-sown peas

Removing the growth tip directs energy to the rest of the plant

Q My dahlias are toppling over in the wind. What can I do?

Q What can I do about the critters eating my dahlias?

Judith High, West Yorkshire

ABOB SAYS You’ve done well to deal with the earwigs, vine weevils and slugs, however I think these may persist, and in some number, as the dahlias’ surroundings, as shown in the photo you sent in, are quite congested and hard to police.

Sadly, dahlias are tasty to most herbivorous pests, so their damage is unlikely to be caused by just one muncher. I guarantee, if you go out on a warm, damp night with a bright torch you will see a convoy of fat snails as well as surviving slugs, and if you sneak up quietly so as not to disturb them, platoons of earwigs chomping away.

Furthermore, I wonder if by now your soil and plants have become tired, so they’ve not enough vigour to grow strongly. I suggest you propagate new plants: grow these in the same place but in large tubs, stood in double saucers with the gap between the saucers filled with water, thus safely moated.

Peter Tucker, Essex Q&A A MATT SAYS If you pinch HOT out dahlias as young plants they become bushy, rather TOPIC than tall. When they are Dahlias about 25cm tall with four sets of leaves on strong stems, cut the main stems just above the top pair of leaves. The stems below will produce side shoots, making the plant bushier and more floriferous.

Pinching out delays flowering, too, so leave some shoots and remove others to prolong the display. You can extend flowering still further by pinching out new side shoots that appear later on.

If your dahlias are producing flower buds this month, you may want to leave them to bloom, because we’re nearing the end of the season. You may still need to stake your plants because of the weight of the foliage and blooms. Dahlias’ exuberant blooms can make them unstable and top-heavy

Q How do I move my eight-year-old bay?

J Page, by email A MATT SAYS Established plants are hard to move but now is a good time, while the soil is warm. Dig around the plant for a large rootball, tidy up damaged roots with secateurs, then replant at the same level as before, and mulch. Stake if needed. Water well after planting, and through next year.

Take the largest rootball possible to avoid feeder root damage

Q I’m not sure what rambler

this is. Should I prune it?

Cheryl Finnigan, Lancashire

ACHRISTINE SAYS I don’t think this is a rambling rose – it looks more like a climber. Ramblers tend to produce several strong, long stems with few side-shoots.

Some modern varieties are very difficult to tell apart, so for now, ask yourself the question – does it need pruning? If so, remove up to a third of the growth and then tie in the remaining stems. Cut out any dead, diseased or damaged shoots, and any that are crossing.

You may be able to get the plant identified by taking some of the flowering stems to a rose show. Then it would be easier to know what to do with it in the long run.

Ramblers will grow strongly from the base, with one flush of flowers

Q My ipomoea won’t flower but my daughter’s has. Why?

Rowlie Price, by email A MATT SAYS Ipomoea need the heat of a warm summer in a sheltered, sunny spot – even better if it is against a south- or west-facing wall. Once the plants are established, feed them with tomato fertiliser to encourage lots of flowers. Mexican native Ipomoea lobata

prefers hot, sunny conditions

Autumn’s arrival

As summer draws to a close, look out for the Woodland Trust’s key signs of autumn

There’s always something magical about watching the seasons change, and by now you’ve probably already noticed the beginnings of autumn, both in your garden and beyond.

For meteorologists, autumn begins on 1 September as the year is split into quarterly seasons based on annual temperature cycles. But, in the astronomical calendar, the start of autumn is marked by the equinox later in September, when the daylight and dark hours are equal.

It might not always feel like autumn on these dates, but the Woodland Trust highlights many signs in nature that indicate the seasons are changing.

If you spot any of these signs, you can record them through the Woodland Trust’s Nature’s Calendar project. By adding to this dataset, you’ll be helping the charity to track the effects of weather and climate change on wildlife across the UK.

Signs of autumn

Here are a few of the main changes to look out for: Leaves change colour as there’s less sunlight, so deciduous trees stop making chlorophyll (the green pigment in leaves) and fade into rusty autumnal hues. Many birds, including cuckoos, swifts and swallows, migrate south to warmer climates for the winter, while others, such as redwings, fieldfares and waxwings, arrive in the UK from colder countries. Seasonal fruits begin to appear, from blackberries in bramble bushes to hedgerows bursting with elderberries, sloes and rosehips. Various tree and plant species also undergo noticeable changes – ivy starts flowering, fungi thrives in the damp weather, and tree seeds, like acorns and conkers, ripen and fall to the ground.

To become a member of the Woodland Trust from just £4 a month, scan the QR code or visit woodlandtrust.org/join