How to grow Succulents

How to grow and care for succulents such as sedum and sempervivum, including advice for propagation and overwintering.

Most succulents come from hot countries and they need protection over winter because they are not fully hardy. Most will survive in an unheated greenhouse if fleeced, but there are usually some losses. However, there are some hardy succulents – principally houseleeks and sedums.

What is a succulent?

‘Succulent’ covers a wide range of plants, some hardy and some decidedly tender, however they all share one characteristic: they have fleshy stems and leaves that carry water.

This makes them drought tolerant so they are ideal plants for hot, sunny positions. The water they store helps them through dry summer months, so if your watering regime is less than perfect these sculptural plants are for you.

Succulents store water because their root systems tend to be shallow, so all succulents (hardy or not) will resent cold, wet soil at their feet – especially in winter.

Many succulents have glaucous leaves arranged in a rosette. Others have tiny leaves similar to bladder rack seaweed. Some have linear leaves. Mixed together, they provide an interesting mix of textures. Spines and web-like hairs put off grazing animals in the wild but, despite this, succulents are a lot kinder on the fingers than prickly cacti.

Single specimens can look stunning grown alone, especially once they mature. Galvanised metal is an especially suitable material: it frames the greyer varieties perfectly. However there are burnished blacks, warm-golds, warm-red and variegated creams and greens on offer too.

Where to plant?

Succulents need a warm, sunny well-drained position to develop their foliage colour.

Most succulents will be grown in containers and pots and they will need good drainage. Add coarse grit to soil-less compost and repot every year in late-spring.

Don’t worry about damaging the roots when re-potting: these plants tolerate disturbance.

Overwintering succulents

When summer begins to wane, begin to dry off the plants by moving them against a house wall where rain cannot penetrate the roots.

Get them as dry as you can before putting the hardy pots somewhere sheltered.

Place the tender succulents in the greenhouse with a frost-breaking heater.

Fleece them well in cold weather.

Clean any mouldy or dead leaves away regularly.

Revive them in March, with a drink.

If they look dead give them at least three months before throwing them away.

How to propagate succulents

Succulents are easy to propagate in almost all cases.

Those that produce new rosettes can have babies pulled away.

Individual leaves root easily in horticultural sand if left to for a day so that the wound calluses over. Nurseries often dry them off completely before propagating them.

Small succulents rosettes keep for many weeks and they will still grow away.

Pests

Vine weevil

Always check for vine weevil: they adore the fleshy leaves and stems. Should you find any, bin the plant but pull off some leaves or a smaller rosettes and pot these up.

Succulents thrive on poor soil. They do not need feeding as long as they are repotted in good compost and grit every year.

Pebbles throw up heat and single specimens in pots can be made to look much better with grit or small stones round the base. This layer will deter pests.

Houseleeks, or sempervivums

Houseleeks are hardy enough to withstand British winters, although they do tend to get ragged during hard winters. They normally grow away in spring and by early summer they look handsome once again. Houseleeks spread by forming new rosettes and four or five new rosettes usually form each year giving rise to the common name Hens and Chicks. Once the rosette gets large enough, a flower spike will appear. After this, the rosette dies leaving the baby rosettes more space to grow.

Basically, sempervivums are monocarpic – they die after flowering. If a houseleek gets stressed (if it’s too hot and dry) it will flower and set seed more quickly.

Six varieties of sempervivum

There are many to choose from that are equally good.

‘Reinhard’ AGM
Eye-catching vivid emerald green rosettes with black tips.

‘Virgil’
Unusual bluish purple leaves with dark tips

‘Sioux’
Medium-sized pinkish red and glowing orange rosettes

‘Rotkopf’ AGM
Shapely pink-brown leaves

‘Othello’ AGM
Echeveria-like enormous dark-red rosettes

‘Lilac Time’
Large pale-lilac rosettes

Hardy sedums

The smaller, low-growing sedums make excellent partners for all succulents. Many are hardy, but not all.

Sedum sieboldii (Japanese orpine)
Flat waxy leaves with a red hue topped by pink starry flowers. Sprawls well – hardy.

Sedum prealtum
A shrubby sedum that can reach over two foot in height, producing stems topped by green leaves margined in red. A Mexican species for a hot spot – not totally hardy.

Sedum morganiacum (Donkey’s Tail)
Hanging branches of overlapping blue-grey leaves arranged in a dense spiral. Probably Mexican. Treat as a tender.

 

 

Pest & Disease watch this month!

Pest and disease watch

Inspect lilies for the scarlet lily beetle whose larvae can strip plants in days.

Vine weevils can also be a problem at this time of year.

Small holes and tears in new foliage of ornamentals such as Caryopteris, Fuchsia and Dahlia are most likely caused by capsid bug damage.

Watch out for aphids (greeenfly and blackfly) on stems and leaves of young shoots.

Sudden collapse of apparently healthy clematis, especially the large-flowered cultivars, could indicate clematis wilt.

In dry weather powdery mildew can play havoc with plants such as clematis, roses and Lonicera.

Look out for and treat black spot on roses and scab on Pyracantha.

How to grow Strawberries

Strawberry-Malling-Centenary-1300312

Grow

Water frequently while new plants are establishing. Also water during dry periods in the growing season. Water from the bottom as water from overhead can rot the crown and fruit.

During the growing season, give strawberry plants a liquid potash feed – such as a tomato feed – every 7 to 14 days. In early spring, apply general fertiliser such as Growmore at a rate of 50g per sq m (2oz per sq yd).

In a heated greenhouse or conservatory, it is possible to bring forward flowering by several weeks, so long as the temperature does not go above 16°C (61°F), because this will inhibit flowering. You will also need to hand pollinate the flowers.

As fruits start to develop, tuck straw underneath them to prevent the strawberries from rotting on the soil. Otherwise use individual fibre mats if these are not already in position. The straw or matting will also help to suppress weeds. Weeds that do emerge should be pulled out by hand.

After cropping has finished, remove the old leaves from summer-fruiting strawberries with secateurs or hand shears. Also remove the straw mulch, fibre mat, or black polythene, to prevent a build-up of pests and diseases.

Expect strawberry plants to crop successfully for three years before replacing them. Crop rotation is recommended to minimise the risk of an attack by pests and diseases in the soil.

Plant

Strawberries are so versatile – they just need sun, shelter, and fertile, well-drained soil. Avoid areas prone to frost and soils that have previously grown potatoes, chrysanthemums, or tomatoes because they are all prone to the disease verticillium wilt.

Buy plants from a trustworthy supplier so that the cultivars are what they say they are and the plants are disease free. Order plants in late summer so that they can be planted in early autumn. Strawberry plants bought as cold-stored runners should be planted from late spring to early summer and will fruit 60 days after planting.

Runners look like little pieces of roots with very few leaves. Don’t be alarmed, this is how they should look. You can buy runners from late summer to early spring, and they should be planted in early autumn, or early spring (avoid planting in winter when the ground is wet and cold). You sometimes also see strawberries for sale in pots (normally from late spring onwards) and these can be planted as soon as you buy them.

Strawberries are traditionally grown in rows directly into the garden soil – often referred to as the strawberry patch. Avoid windy sites which will prevent pollinating insects from reaching the flowers. In poor soils grow in raised beds, which improves drainage and increases rooting depth. Alternatively, try containers or growing-bags.

Strawberry plants can be grown under a tunnel cloche to produce an earlier crop by up to seven to 10 days. Place the cloche over the plants in early spring, but remove or roll up the sides when the plants are flowering to give pollinating insects access.

Strawberries in containers can also be grown in an unheated greenhouse, which encourages an even earlier crop, by 10–14 days. In a heated greenhouse or conservatory, it is possible to bring forward flowering by several weeks, so long as the temperature does not go above 16°C (61°F), because this will inhibit flowering. You will also need to hand pollinate the flowers.

Harvesting

Pick strawberries when they are bright red all over, ideally during the warmest part of the day because this is when they are at their most tasty.

Eat them as soon as possible; they do not keep well, but some can be frozen or made into preserves.

Lawn care this May

green-lawn

Keep on top of weeds

Mow regularly and continue adding clippings to the compost heap.

Use the half-moon edging iron, or a spade, to create a 7.5cm (3in) gutter around the lawn edge. This will prevent grass from creeping into the border from the main lawn.

Apply a high nitrogen summer lawn fertiliser to encourage a healthy-looking lawn, taking care to avoid any runoff as this may cause pollution. Always follow the manufacturer’s instructions carefully.

Sowing new lawns or over-seeding dead patches can still be carried out in early May. Prepare the ground for sowing, by cultivating, levelling and lightly firming beforehand. Do not walk over or mow newly sown grass until it has reached a height of 5-7.5cm (2-3in), and then only give it a light trim at the highest setting.

Ensure new lawns (either from turf or seed) do not dry out during dry spells. Keep off them for as long as possible to allow establishment. Don’t worry over a flush of weed seedlings in newly seeded turf. These will disappear once regular mowing begins.

If moss is a problem, choose a combined fertiliser and mosskiller when feeding the lawn.

Selective lawn weedkillers will kill the weeds but not the grass or any naturalised bulbs. However, be warned – they will kill wild flowers growing in the turf, and damage border plants they come into contact with.