As we head into June with another Bank Holiday to see May out, the weather looks like it is going to be a mix of rain showers, occasional strong winds & dry spells continuing into the first week of June. As we go further into June the weather is likely to remain unsettled with slightly drier and less windy weather likely across northern parts of the UK, this being punctuated by cooler, showery spells as weather systems arrive from the west. Unfortunately not only will your flowers & vegetables flourish in these conditions but the weeds wil benefit too, so choose a hot day to hoe them off & they will shrivel & die. It should be safe to put out your tender plants in most areas of the country but harden them off for a few days first & keep an eye open for low overnight temperatures. Make sure you keep your plants watered during dry spells & don't forget to start feeding container plants later on in the month as compost feed only lasts 6 weeks. If you haven't done it already, it is also a good time to check over your garden furniture & barbecue to make sure that they are clean & in good condition & that you have cushions, parasol, barbecue fuel & everything else you will need for relaxing in the garden.
Planting & Sowing
- Plant roses - If a rose is pot-grown it is very possible to plant it in full bloom. To help it along, place special rose compost in the planting hole.
- Plant summer flowers, they grow even faster in June than May. If plants are in pots, don't forget that pot soil only contains six weeks' worth of nutrients. After that you will need to feed weekly to get an outstanding performance.
- Nature has started flowering now, but there is still time for planting: what about some scented old-fashioned style roses. Or how about creating a new border? Take your shopping list to the garden centre & at the end of the day you will have added a new area to your garden.
- Biennuals are magnificent. Think of wallflowers (Cheiranthus), honesty (Lunaria) and other varieties. You can sow them now to plant in the autumn & flower next year.
- Continue to sow salad crops every 2-3 weeks for a constant supply.
- Plant out courgettes, squash, cucumbers, sweetcorn, peppers, runner beans & dwarf runner beans.
- June is a good time to take softwood cuttings of many deciduous shrubs.
Cutting & Pruning
- If you cut delphiniums back after the first flowering, they will flower again in the autumn.
- June is the month for pruning cherries, but don’t remove heavy branches because of diseases like silverleaf and gumming. Also prune wall trained plums & cherries, cutting out weak or badly placed shoots, shorten others to 6 leaves.
- You can still prune the spring-flowering shrubs which have finished flowering now. If you wait too long with this, there is a risk that the new flowering branches for next year will not ripen sufficiently and will not be winter-hardy. Remove some older wood to encourage new growth.
- Tie climbing roses - You should not prune climbing roses now. Leave them to develop and grow plenty of new shoots. Tie them in to prevent the plants from ‘falling over'.
- From 21 June hedge plants go into a second period of rapid growth so if you prune now they will rapidly recover and form many young shoots (make sure there are no nesting birds first). Prune taxus and buxus hedges when it is cloudy.
- Place straw or matting around strawberries to keep the berries clean & away from slugs & snails.
- If you live in a dry part of the country & need to conserve your water, prioritise your watering to container & newly planted bedding plus leafy vegetables.
- Harvest ‘new’ (early) potatoes when the plants start to flower.
- Move Cymbidiums & other house plants out to a shady area of the garden for the summer & remember to water them.
- If you have tree ferns it is best to water them at the crown rather than the base.
- Tidy up Hellebores by removing the dead leaves & stems. You can collect their seeds & sow immediately onto the surface of a mix of John Innes seed compost & multipurpose compost. Cover with a thin layer of horticultural grit, water & stand outside in a warm shaded area. Keep the compost moist but not wet over the summer & seedlings may be seen from autumn onwards.
- If you have a garden pond remove blanketweed & duckweed which result from excess nutrients. Now is a good time to add aquatic plants to your pond. They will provide some shade & compete for nutrients to reduce blanketweed & algal growth.
- Cut back flowered stems of Euphorbia as they can be susceptible to mildew.
- Cut back Oriental poppies after flowering unless you want them to self-seed, although there may still be time for a second flush of flowers if cut back.
- Thin out direct sowings of hardy annuals to give the ones that are left a better chance.
- Divide bearded irises after flowering.
- Damp down greenhouse floors to raise humidity & discourage red spider mite.
- Rhododendrons & Camellias that have finished flowering are best ‘dead headed' (pinch out the dead flowers) to guarantee profuse flowering next year. Pull them off with a little bit of stem: the flower buds for next years are directly underneath. Most varieties have finished flowering by June. If you pull off the dead flowers now, this will prevent seeds from forming and the plant will invest even more energy in producing new flower buds for next year.
- Weeds grow fast in June – keep on top of the weeding or they will steal precious nutrients & water from your flowers.
- Dig up tulip bulbs once the foliage has died back completely.
- Give support to perennials that need it. Careful not to bind the stems together into bunches. Place canes in between in the direction of growth and tie them to those.
- Roses exhaust the soil in which they are growing quite quickly. So it's ideal to give them special rose fertiliser which contains trace elements and magnesium.
- The lawn has a lot to cope with now so give it some TLC.
- Ensure sufficient nutrients. Special slow-release lawn food is best. Scatter other fertiliser every six weeks. Preferably do this on a rainy day or spray immediately after scattering.
- Do not water every day - if it is possible, once every three to five days is better. This will force the grass to root deeper and it will not dry out so quickly.
- Mowing or mulch mowing - You can mow the grass and remove the cuttings, compost them or scatter them between the ornamental plants, or you can ‘mulch mow'. A special set of cutters on the mower chops the cuttings up so fine that they can remain on the lawn as mulch and thereby act as a direct fertiliser.
- Cut a play lawn to three centimetres and an ornamental lawn to two centimetres, but set the mower a bit higher during dry spells.