June gardening tips

Early June

Mulches help to conserve water but the soil must be moist before they are applied. Sow quick growing hardy annuals e.g. clarkia, Virginia stocks for late colour in dull spots.

When watering concentrate on climbers on walls, container and basket plants, newly planted items, dahlias, sweet peas, leafy veg. crops, celery and fruit bushes.

Dig up bare centred alpine plants and divide them, re-planting the young pieces from around the edge.

If you use nematodes to control vine weevil grubs buy them online or mail order. They are also available at some garden centres through the Agralan company.

June is one of the worst months for pest and disease attacks, so check plants regularly. If using a trigger spray product remember to shake it first and there are lots of safer “organic” treatments available now.

Mid June

Make sure plants in tubs and baskets are fed regularly, as well as watered. Many climbing plants can be increased by layering at this time of year.

Mow the lawn to leave the grass 2.5cm (1in) tall. Makes grass more drought resistant. Treat established lawns with a lawn weed killer but not if there is a drought.

Dead head rhododendrons after flowering to encourage new growth.

If you need more fish in your pond this is an ideal time to introduce them but goldfish can be detrimental in a wildlife pond.

When picking strawberries always remove any rotting fruit, otherwise problems increase.

Watch out for cabbage white butterflies around your brassica plants. If you do not like to use chemical sprays, try Grazers G3 organic caterpillar repellent. They also make good repellents for slugs and lily beetles too.

Sow radicchio now for winter salads. Choose a good coloured variety like pallo rossa.

Sow salad crops regularly, in small amounts, sowing the second row as the first emerges. Tomatoes can be planted outdoors. Select a sheltered site and support the plants.

Take cuttings from dianthus (pinks). They root easily nowin a shady spot.

Lettuce will not germinate in hot weather. Sowing in moist drills in late evening helps.

Shade the greenhouse, ventilate it well and spray water over the floor to raise humidity.

Take softwood cuttings from shrubs. Remove 7.5 cm (3in) of shoot tips. Root in pots of gritty compost, placed in polythene bags, in a shady spot.

Late June

Lift and divide flag iris after flowering. Re-plant young growths, keeping rhizomes above soil level.

Prune back side shoots on cytissus (broom) after flowering to keep plants neat.

Deadhead roses regularly to prolong flowering.

Remove any “suckers” as soon as they appear.

Watch out for algae / blanketweed in pools. The introduction of a product based on barley straw can provide an organic control measure.

Feed tomato plants regularly from when first fruits begin to form, using tomato food.

Take out one third of the older branches on deciduous shrubs, like Philadelphus, Weigela and Deutzia after flowering.

Put cymbidium orchids outside in a sheltered, shady spot until late autumn. Keep them well watered and fed over this period.

If pollen beetles infest your cut sweet peas, put them in water in a shed for a while. The beetles will fly into the window attracted by the light.