Gardening Jobs of the Week, May 7, 2011

We may be looking summer in the face but there are still a few spring clean up jobs to be done. Forsythias will have finished flowering by now and if you have not already done it they need to be pruned down. Forsythia is very tough and you will not kill them with a good hard prune. Start by removing any straggly bits that are wildly out of shape, then remove any crossing branches, next look for any non-typical or damaged or dead wood and remove that. If you have not remove at least a third of the overall plant then take out some more up to about a third. Don't leave it too late to prune them and never prune them back in the autumn. It is worth feeding the shrub with a decent amount of bone meal or similar fertiliser and apply a mulch of garden compost or well-rotted organic matter.

•Evergreen hedges should be now coming back into growth, so it is worth giving them a spring trim. After a rough winter they can look a little unkempt. Spraying the hedge with water will help keep the cuts moist and trigger the dormant buds into fresh new growth. •This is the time to plant out dahlia tubers into the garden; although these are tender they will cope with any light frost. Plant them into well-prepared soil, dahlias are greedy feeders, they will use up all the nutrients you can give them, try and incorporate plenty of organic matter before planting. Insert a stake to support the plant as it grows before planting, this will avoid damage to the tuber later. The tubers should be planted so that the crown of the tuber is at least 7.5cm deep.

•Although the spring is a happy time looking forward to bright summer bedding displays it is also a sad time as over the next couple of weeks we remove the winter and spring bedding. Wallflowers, myosotis and other spring bedding need to be removed so we can prepare the soil for the summer bedding. Add plenty of well-rotted organic matter and some fertiliser ready for petunias, lobelias, busy lizzies, pelargoniums, fuchsias and other summer bedding plants later this month.

•Pelargonium and fuchsia cuttings taken a few weeks ago should have rooted now and will be growing away strongly. They may well be ready to pot on, so carefully lift one or two and have a look at the roots. If they have a good root system then pot them up in 9cm pots. Pinch out the shoot tips to encourage bushy growth – this should be done when the plants are 10-13cm tall, unless you fancy trying to grow a standard fuchsia. If you want to try that, leave the top shoot alone, and as they grow keep potting them on and train them up a cane to keep the stem nice and straight, remove side shoots as they grow, and pinch the top out at the desired height.

•Now is the time to plant up hanging baskets with half-hardy summer bedding plants like pelargoniums, lobelia and petunias. Try to select plants that will complement each other in the basket all with similar colours. Keep them in a cool greenhouse or porch to establish before putting out later this month.

•Keep a look out for aphids settling in for the summer on your fruit trees. It's a good idea to get them under control early in the year. I don't like using chemicals on food crops so I go for the organic option of soft soap applied eight days after petal fall. Avoid spraying fruit bushes and canes when in flower as this may harm the pollinating insects.

•Fast-growing crops include radish and lettuce especially the smaller varieties that will mature rapidly. You could also consider cutand- come-again types of vegetable such as leaf beet and spinach which can be planted between rows of autumn-maturing crops such as Brussels sprouts and leeks.