Best of the bunch - Cranesbill geranium

This perennial plant is perfect at the front of borders, to fill in gaps where otherwise weeds would grow and to add colour to the scene. Generally easy to grow, the compact types grow to around 15cm tall, are good for rock gardens, while mat-forming plants make good ground cover in woodland gardens and taller, clump-forming species and hybrids look great in a border or among shrubs.

Good varieties include Geranium 'Orion', whose striking violet-blue flowers stand out in herbaceous beds, while G. 'Ann Folkard' produces magenta flowers from May to October with a foil of yellowish young foliage ageing to light green. A real winner is g. Rozanne, which was the winner of the RHS Chelsea Flower Show 'Plant of the Centenary' this year. Good companions for the soft mound shapes of these hardy geraniums include plants with a strong outline, such as phormiums, tall alliums or irises. Cut them back in mid-summer if they start to look tatty.

Good enough to eat - Thyme

If you love colour but aren't very good with maintenance, a pot of fragrant thyme may be the way to go, providing you with leaves for the kitchen and pretty flowers for the garden. Some are not really culinary plants but are grown for their flowers, so make sure you pick up the right type if you want to use it for cooking. Thyme needs to be planted in a sunny spot in poor, well-drained soil or in a terracotta pot filled with John Innes No 1 potting compost mixed with 50% potting grit to make a well-drained mix.

The best time to plant is early summer, after the last frosts, spacing busy, upright types 23cm (9in) from their neighbours and spreading varieties 30cm (12in) apart. Water them in and water again in dry spells until the plants become established, after which time you won't need to water them much at all, and don't feed them. Good culinary thymes include T. vulgaris, which has strongly flavoured, short leaves and deep mauve-pink flowers in June and July, and T. x citriodorus, which has lemon-scented leaves and a slightly milder flavour. To harvest, snip young shoots from the tips of the stems.

Three ways to... Make the most of fertiliser

1. Use granular or powder fertilisers on moist ground, then hoe them in. If the soil surface is dry, water well in.

2. Don't apply feeds when plants are under stress due to water shortage or attack from pest or disease, nor in dormant seasons.

3. Always follow the recommended rate of use. Too much fertiliser can scorch plant roots. If you over-apply by mistake, drench the compost with plenty of water to wash out the excess.

What to do this week

:: Prune large and overgrown Clematis montana after flowering, cutting back hard to encourage new growth.

:: Continue to earth up potatoes to encourage them to root into a ridge of soil and develop a larger crop.

:: Top up pond water levels as they fall in hot weather.

:: Place a small ramp into steep-sided pools and water features so that small mammals like hedgehogs can climb out if they accidentally fall in

:: Give extra water to plants growing at the base of walls where the soil can remain dry despite rain

:: Pinch out the tips of trailing plants in hanging baskets to make them branch out. Pick off dead flowers every few days.

:: Sow seeds of wallflowers in a corner of the garden to transplant in the autumn

:: Use a soap-based spray to deal with heavy infestations of aphids

:: Continue slug patrols in the cool of the evening, or early morning, or after rain, to protect vulnerable plants

:: Buy bulbs for autumn blooms, including Nerine bowdenii, colchicums and autumn crocus

:: Take cuttings from osteospermum, fuchsia, pelargonium and argyranthemums, root them into small pots to produce young plants to keep through the winter

:: Take soft and semi-ripe cuttings using non-flowering shoots of shrubs such as cotinus, potentilla, hydrangea, spiraea and weigela.