Summer harvest

This year, crops have been off to a very slow start, probably as a result of the cool spring we’ve had. Tomato plants growing outdoors have been sitting unsatisfied with the lack of sunshine and temperatures, something often in plentiful supply where they thrive in the Mediterranean. Squashes have suffered a similar fate. Fear not however: as temperatures rise, plants have a knack of catching up.

A crop that has grabbed my attention this year are the globe artichokes growing at RHS Garden Harlow Carr. This Mediterranean thriving plant also enjoys lots of sunshine, but thrives when temperatures are cooler. In the Mediterranean, artichokes crop much earlier to avoid the intense summers. We have been cropping our artichokes at Harlow Carr since late spring and they are still growing prolifically, thriving in the cooler weather.

Thought to have originated in the Mediterranean, the globe artichoke is a frost-tender, thistle-like perennial that grows from a short rhizome and can reach heights of up to 2m tall. Part of the Aster Family, Cynara scolymus’s, the name originates from Greek, with Cynara referring to the thistle-like spines on the flower head, resembling dog teeth. Artichokes can tolerate most soil conditions, providing it is fertile and well drained and the site is not too hot. A mild climate with a sheltered position is ideal for this plant to thrive. In a good season, one plant can give you over a dozen flower heads that can be eaten or allowed to flower, giving a highly ornamental display.

Plants can be propagated by offsets from the base of established plants. Cut these side shoots below the soil line with a short length of root in spring and plant them in your desired position 90cm apart. Plant at a depth of 5cm and trim the end of the leaves to about 13cm in length so that they do not lose much water through transpiration. If there is a danger of frost, protect the plants with fleece. Globe artichokes can be propagated by seed but the results can be hit and miss. To propagate seeds, sow in modules and keep temperatures in excess of 15°C until they germinate. Prick out into 10cm pots when large enough to handle, protecting seedlings from frost. Try to grow them on in cool conditions, between 2 and 10°C, prior to planting out in early summer when the soil has reached at least 16°C.

If winters are severe (below -10°C), plants may die. To prevent this, earth them up and cover with straw. Every three to five years, plants crop less prolifically so a constant offset propagation regime will ensure you always have a heavy crop.

Globe artichokes are generally pest-free crops but suffer from the usual slugs and snails, aphids and earwigs.

Make sure you don’t leave it too late to harvest. Harvest the top artichoke - referred to as the ‘King Bud’ - when the bottom scales begin to open and it is plump and soft. Cut the artichoke with the stem at the leaf node below. Often a smaller artichoke is growing from this point. Cut the flower head from the stem at the base and peel away the outer leaves until you reveal the pale yellow ones. Trim away the dark green leaf bases where the stem was cut and cut the top off about 1cm in. Chop the artichoke in half and remove the fibrous hairy choke in the middle with a teaspoon. Some varieties do not possess a choke that needs removing. Here at Harlow Carr we have an Italian variety named ‘Concerto’ which produce medium-sized purple flower heads without the choke; they taste delicious.

There are a number of things you can do with artichokes. Boil them in vinegar and lemon juice until cooked. Dry them off and then preserve them in olive oil - often the method used by supermarkets. Once preserved they can keep for up to six months and can be added to salads and pizzas or just simply eaten on their own with fresh bread. Alternatively, simply add them to fresh tomato sauces or soups. Once you develop a taste for them you will gladly sacrifice the ornamental splendour of their flowering and wait in much anticipation for their arrival the following season.

Jobs to do

• Regularly pinch out and tie cordon tomatoes.

• Summer prune gooseberries and white and red currants.

• Regularly tie in sweet peas, peas and beans.

• Apply layers onto your compost heap (grass clippings, cut up twigs and dead leaves)

• Ensure all brassicas are netted, protecting from cabbage caterpillars.

With thanks to Francesco Ponziani, Horticulturist at RHS Garden Harlow Carr

For more information on things to do in the garden this month visit rhs.org.uk

DIARY DATES

9, 16 and 23 July: Lazy Summer Evenings

Visitors can enjoy the beauty of Harlow Carr as dusk settles on three Thursday evenings throughout July. Bring a picnic and a bottle of wine or treat yourself at Bettys Tea House in the garden. There will be live music on the lower lawn from 6 – 8pm. Last entry is 7.30pm and the garden closes at 9pm. Members can bring two guests free of charge and non-members pay half-price admission after 5pm.

11-12 July, 10am – 4pm: The National Sweet Pea Show

Top Sweet Pea growers from up and down the country enter this prestigious weekend-long national competition which promises visitors the sights and breathtaking scents of what can only be imagined from hundreds of vases filled with Sweet Pea blooms. Members of the National Sweet Pea Society will be on hand to offer expert advice, and bunches of their beautiful surplus blooms will be on sale. Normal garden admission.