Gardeners’ Question Time

Bob is an organic gardener and has designed his garden to produce lots of veg, fruit and cut flowers. 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.

Carole Lambourne, Staffs

ACHRISTINE SAYS Sea air and weeks without being tended to are quite a challenge for any plant in a pot, so you are going to need larger containers than you think, remembering that small ones dry out very quickly.

Use a soil-based compost. Place the containers on pot feet so they can drain over wet periods, and ensure they have drainage holes.

Erigeron glaucus grows up to 40cm tall, producing large, pale-purple, daisy-like flowers above grey foliage. Normally it is evergreen and should cope with this planting position. Griselinia littoralis ‘Variegata’ is an evergreen shrub with thick, waxy, variegated leaves and should cope planted in nothing smaller than a 45cm pot.

Also take a look at the wide range of escallonias now on offer. Their flowers can be white, red or pink, contrasting with dark evergreen foliage. They vary a lot in ultimate size, so check the label to find one that’s right for you. Q&A

Seaside pot s

Festuca glauca ‘Elijah Blue’ will grow well in a large pot in full sun

AMATT SAYS Mediterranean plants and grasses will survive in free-draining compost.

Try lavenders like pink ‘Little Lottie’ , paler ‘Hidcote Pink’ or late, white ‘Heavenly Angel’ .

Herbs will also thrive, including sage, bay, thyme and also oregano ‘Kent Beauty’, whose trailing stems are covered with pale, rounded leaves and tubular, pink flowers surrounded by overlapping, deep rose-pink bracts in summer.

For grasses, Eragrostis curvula ‘Totnes Burgundy’ has long, trailing leaves that turn a deep burgundyred as they mature – it definitely needs a tall pot. Pennisetum thunbergii ‘Red Buttons’ has bright red, button-like flowers, floating above mounds of green foliage from midsummer. And the semi-evergreen Festuca glauca ‘Elijah Blue’ forms spiky mounds of fine blue leaves.

J Pike, by email A BOB SAYS Most chillies change colour as they ripen, usually going red or purple, though some – such as habaneros – may go orange. They can be picked to use fresh even before the colour changes but they will be more flavoured and process better when left longer, and for drying this is certainly so.

Fortunately the plants can be perennial if kept warm and bright throughout winter so you don’t need to pick fruits until required. However they may be affected by mould, so it’s better to pick and process most of them.

Drying chillies is easy: tie them along a thread and hang somewhere warm and dry, then put in a sealed jar in a dark cupboard. You can also freeze chillies in a bag, or you can pickle chillies by cooking them in a sugary, vinegary mix (which if you like can then be liquidised into a hot sauce) or by simply immersing them in vinegar.

Clematis viticella ‘Abundance’ grows to three metres in height

Sally Bevan, Essex A CHRISTINE SAYS Firstly, improve the soil that you presently have by adding as much organic matter as possible: ideally, wellrotted compost or animal manure. This will act as a sponge, retaining water that plants can access during dry spells.

Consider mulching the beds in the winter or early spring, once sufficient rain has fallen to penetrate the soil to some depth. This could be an organic material such as a decorative bark or something inorganic such as a coloured glass or stone.

If you use an organic material it will need topping up each year. Remember to keep it away from the stems of plants as it can cause rotting if in contact with the stems.

Michelle West, by email

AMATT SAYS Clematis would serve you well. Either grow one that’s slightly larger than the roof, then give it a haircut when needed, or use smaller hybrids and cut them back each year.

Clematis viticella ‘Abundance’ is fast-growing with lots of deep pinkpurple flowers from midsummer to early autumn. Clematis x jouiniana, a hybrid of a herbaceous clematis and our native old man’s beard, is a scrambler with frothy trusses of white flowers in late summer and early autumn; the variety ‘Praecox’ has pale blue flowers.

Just remember that the fallen leaves of any deciduous climber will need removing periodically to stop a build-up damaging the roof.

Kevin and Karen, by email A BOB SAYS First, slow compost is not bad in itself – but is perhaps indicative of a cool heap. I’d make your piles higher if possible – I pack mine above shoulder-height. Heat rises, so bigger heaps really cook.

Next, more variety of materials helps, and extra material also adds to the depth more quickly. Scavenge more garden waste, even consider soliciting neighbours’ contributions, and – as I’m infamous for – human urine is a brilliant, free, compost stimulant. If not pee, then add more water – if it’s too dry it will be slow.

Plastic sheet is sufficient to keep in moisture but several layers of it, or some bubble wrap, would be better at retaining heat. A roof would just get in the way.

Glynis Brown, by email

ACHRISTINE SAYS Nerines do best when left undisturbed, but if they become overcrowded like yours then knock them out of the pot in spring or early summer while they are dormant and divide the bulbs up individually.

Retain the smaller ones, potting these up and growing them on, as these will go on to flower once they reach a suitable size, normally in two to three years. Replant the larger bulbs into a free-draining hot border for them to do well.

If in the south, plant with the tips of the bulbs just below the surface of the soil, but if in colder parts of the UK plant slightly deeper to give some protection. Discard any that are diseased or damaged.

Erysimum ‘Bowles’ Mauve’ lasts several years and is easy to grow

Ian Tomisson, by email A MATT SAYS Growing the same plant year after year in the same spot leads to nutrient deficiency and sometimes pest or disease problems, so improve the soil by mulching with well-rotted organic matter. Brassicas need a good, firm planting bed so make sure that the soil is well firmed by shuffling along the surface on your heels, first one way and then again at a 90-degree angle, and finish off with a rake.

Being brassicas, wallflowers are susceptible to club root – and if they were infected, this would remain in the soil for several years, affecting any brassicas growing there during that time.

You could also grow wallflowers in pots of peat-free multi-purpose compost mixed in with some soilbased John Innes-type compost to give it some extra body, or you could plant the mauve-flowered perennial variety Erysimum ‘Bowles’ Mauve’, which can flower almost all year round. Another perennial wallflower, ‘Winter Orchid’, has coppery-orange flowers that age to purple. Both are an excellent source of nectar for pollinators over a long season.

Margaret Castle, by email

ACHRISTINE SAYS These are made from polythene tubing. Select the length required to cover your bed with, then insert 30cm canes into the ground at intervals that cover the bed and on each side of the bed.

Push the end of the tubing onto each of the canes to secure them and then cover the bent tubes with either netting or fleece.

David Brown, by email

ABOB SAYS Ants are a food source for a vast range of other creatures, especially woodpeckers, and they also interact with many of our garden ‘friends and foes’, sometimes quite inadvertently to our benefit.

They’re necessary for some other critters such as the large blue butterfly, Phengaris arion, which apparently lodges in their nests, and they also process plant and animal material into fertile soil.

Rachbellact, by email A BOB SAYS Any open container will accumulate rainwater over the year. I suggest inexpensive plastic dustbins with wide openings and a tight lid to keep out debris.

Leave these open only during very wet weather and put their lids back on the rest of the time. If you want the water even cleaner, you can tie muslin or nylon net over the open tops to filter the rain.

Sheila Richmond, by email

ACHRISTINE SAYS Leave the tree in its pot outside for as long as possible. Give the rootball a good soaking a few days before bringing the tree inside.

Position it away from any heatsources, and place the pot in a saucer that holds enough water to keep the roots damp. Exercise extreme care if you are planning to put electric lights on the tree.

Philip Rose, by email A MATT SAYS Cyclamen hederifolium, with white and pink flowers and leaves patterned with silver, would flourish in these conditions; hardy geraniums, too.

Geranium x cantabrigiense ’St Ola’ has bright white flowers in spring and early summer, topping a carpet of evergreen leaves that become red-tinted in winter. Geranium phaeum comes in several forms like whiteflowered ‘Album’, and ‘Lily Lovell’ with lilac-purple flowers.

The white flowers and silvery leaves of Lamium maculatum ‘White Nancy’ form a good ground cover, and sweet woodruff (Galium odoratum) has starry, white spring flowers. The hart’s tongue fern (Asplenium scolopendrium) grows well in dry shade, and Dryopteris filix-mas ‘Linearis Polydactyla’ has unusual crested fronds.

David Preston, West Midlands

ABOB SAYS If there is some moisture in your clay, I‘d most strongly recommend heavilyfruiting and early-flowering shrubs, especially amelanchiers, ribes, mahonias, sambucus and hollies, and under this herbaceous plants such as brunneras, pulmonarias, alkanets and Alchemilla mollis.

However, if it’s very dry the choice narrows considerably, though of course ivy may well succeed on the fence if watered while establishing. I also find that Iris foetidissima, stinking iris, does surprisingly well in dry shade.

Little known but excellent for its early flowering is a comfrey, but not the rampant ‘liquid feed’ sort: Symphytum orientale is compact, with attractive winter foliage and early, bee-friendly white flowers, and it tolerates the most extreme dry shade, once established. And if you’ve the space to let them ramble, brambles are superb for wildlife, though difficult to confine.