Stock check

IN the main entrance conservatory at RHS Garden Harlow Carr we have been growing beautiful Brompton Stocks in containers. This plant seems to have fallen out of fashion over the years as a bedding plant in the garden; occasionally you may see them used in local authority floral bedding schemes but not on a regular basis when compared to the 1970s. The flowers are delicate and come in a wide range of pastel shades including pink, white, purple and magenta. Their beauty is complemented by a pleasant and highly-scented aroma, making them highly prized by florists.

The stock Matthiola incana associates well in containers with another stock from a different genus: Malcomia maritime. The Virginia stock, Malcolmia maritime, is a summer annual and is native to the Mediterranean, growing to a height and spread of 20 to 40cm. It is sweetly scented and can be grown in a sunny site at the front of a border, a rockery or in the front of a container in a similar way as you would use Lobelia Cascade in a summer hanging basket.

Matthiola comes from another genus that holds an even larger range of species and like Malcolmia, comes from the family Brassicaceae. This plant hails from an even wider range in its natural state from the coastal areas in Southern Europe all the way to the Arabian Peninsula. In milder climes it can be grown as a short-lived perennial. The leaves are lance shaped and range in colour from a pale to slightly blue-green form that has fine hairs. The heavily scented flowers are produced from spring to late summer and will last for a considerable amount of time in a cool glasshouse or conservatory.

The cultivars from M.incana are generally treated as annuals and biennials. They will bear a selection of single and double flowering cultivars. “The Ten Week” mixed varieties produce mostly the desirable double flowers in shades of pink, lavender, purple and white and grow to a height of 30 to 40cm.

Matthiola longipetala sub.sp.bicornis (Night scented stock) produce heavily scented flowers that range in a variety of shades and actually increase in fragrance as dusk begins to fall, making it a must- have plant in a summer container by the barbecue. This plant can be seen growing in its natural state from Greece to South West Asia.

Stocks grow best in a fertile neutral to alkaline well-drained soil. They can be started off by sowing seed from early spring in John Innes No.1 compost in gentle heat, similar to sweet peas at a temperature of 10 to 18c. If larger plants are required, sow M.incana cultivars Legacy Series and Excelsior Mammoth in a cold frame in midsummer and overwinter in a cold glasshouse; plant out or pot on for early spring flowers the following year.

Stocks can attract their fair share of pests and diseases. Belonging to the family Brassicaceae, they are susceptible to Cabbage Root Fly and Club Root, however, using root collar mats or a gravel mulch and maintaining a slightly limey soil will do a lot to keep these problems at bay. When growing these plants under glass, always keep them well ventilated and try and avoid getting water on the leaves; this will go a long way to help reduce attacks from the dreaded Grey Mould, Bortrytis and Downy Mildew.

The horticultural industry is trying to encourage us all to have a go at producing more home-grown cut flowers. Stocks don’t require hot growing units to produce their excellent blooms and will grow quiet happily in a cool frost-proof poly tunnel or glass house. With successive seed sowings throughout the year, we could grow these plants for a longer period of time in the UK.

Jobs to do this week

Sow direct sprouts and kale.

Make successive sowings every three weeks of radish, spring onions and lettuce.

Use barriers or protective mesh over carrots to prevent Carrot Fly.

Use root collars, environmental mesh over brassicas to prevent Cabbage Root Fly, small and large white caterpillar infestation.

Continue to harden off bedding plants and tender plants like sweetcorn, summer squashes and outside tomatoes.

Monitor emerging weeds in the garden: hand weed, hoe out.

Mulch around new trees and shrubs and keep moist.

Have horticultural fleece to hand in case of sudden changes in the weather; cover young plants and protect in case of hail showers.

Apply Nemaslug nematodes around plants that are susceptible to slug damage.

DIARY DATES

May 28 to June 5: May Half-Term Family Fun – Scouting for all

Celebrate 100 years of Cub Scouting by getting closer to nature this May half-term. Youngsters can learn about the great outdoors on a special trail through the garden’s woodland; learn how to tie knots and strike a fire on an outdoor workshop; make your own catapult, pitch a tent and develop your pioneering, signalling and tree identification skills. Normal garden admission.