June Gardening Tips

Summer is here. What kind of summer it’s going to be remains to be seen. However, the gardens are soon reaching their peak. All the hard work put in during winter and spring will be starting to bear fruit… quite literally! Most of the sowing, pricking out and potting on will have been done by now and whilst there are always things to be done, watering being a big one, don’t forget to stop and savour all your hard work and enjoy the garden at this time of year.

  1. Remove suckers from roses – Most modern bush roses are grafted or budded onto a rootstock which gives the plants vigour to produce the beautiful blooms we all enjoy. One drawback, however, is that the rootstock itself produces the odd shoot, which is identifiable by its lighter-coloured foliage.  It’s best to pull the sucker off the plant, rather than cut it off, as it’s less likely to grow again.
  2. Tidy overgrown lilacs – If your lilac has become overgrown and leggy, now is the best time for drastic action.  After the flowers have gone, saw or cut them down to about 45 cm from the base and a mass of new shoots will regrow. This will result in a much bushier and better-shaped plant.  Just thin out any inward-growing shoots that cross the centre of the plant.
  3. Prune Clematis Montana – Do this now if you didn’t get a chance last month.  It’s a vigorous clematis, although will only need pruning if it’s getting out of control or smothering neighbouring plants.  After flowering, thin out the growth and trim it back into its allotted space.
  4. Remove old leaves and flower stems of hellebores – by now the foliage of hellebores can be looking a bit tatty. Remove the foliage at ground level, that way,  the new young foliage can be seen growing from the centre of the plant.  A feed with a general fertiliser and a mulch with organic matter will help them come back stronger.
  5. Take cuttings from Dianthus (pinks) – Cuttings from Dianthus are called ‘pipings’ and are easy to root.  Look for healthy, non-flowering shoots.  Then hold the stem about four pairs of leaves from the top and pull the cutting off (this should come away cleanly). Put several cuttings around the edge of a 10 cm pot in a mixture of peat-free compost and perlite. Water them in and place them in a shady cold frame. The cutting will root within three to four weeks when they can be potted into their own individual pots.
  6. Lift and divide bulbs – Once the bulbs have finished flowering, they can be lifted, dried and stored when the foliage has died down. However, if you intend to leave yours in situ year after year, then lift any overcrowded clumps now and divide them up so that they can spend the rest of summer re-establishing.
  7. Plant out sweetcorn – Plant sweetcorn in blocks, 30 cm apart each way rather than in rows.  Why? This is because sweetcorn is pollinated by the wind. By growing the plants in blocks, there is a higher chance of pollination being successful as the pollen will blow onto other sweetcorn flowers.
  8. Check the base of grapevines – Make sure your grapevines are not drying out and give them a regular soak if they need it.  Whether you grow them outside or inside a glasshouse, they are hardy so can cope with our climate. For improved ripening of the fruits, try growing them under glass.
  9. Put up pheromone traps – This is to protect your crops from codling moths. One trap can protect up to five apple trees. Pheromone traps can also help to protect box hedges and plants from the box tree moth. The box tree moth lays its eggs on the underside of the leaves which develop into the larvae of the caterpillar. The caterpillars can defoliate a plant and potentially kill it. Prevention is always better and cheaper than the cure. At Nicholsons, we suggest alternatives to box, available in the Plant Centre, for this very reason.
  10. Dampen down greenhouses – ‘Damping down’ just means spraying or splashing water around a greenhouse to keep the atmosphere humid.  This will benefit the plants enormously, especially if you can close the ventilators and doors for a short time to allow the temperature and humidity to rise and create an excellent growing atmosphere.  It can also reduce the incidence of glasshouse red mite.  After a short time, open the doors and ventilators again to get some airflow back into the greenhouse.