Weather and the Gardener
June may have the longest days, and often brings the most sunshine, but it is rarely the warmest month of the summer. It can, however, be dry, and then the watering problems of May become even more serious.
The favourite way to reduce the evaporative loss of moisture from open soil is by mulching, but a mulch should never be applied too early in the season because it greatly increases the risk of a late frost, the temperature at night over a mulched surface being much lower than that over bare moist soil.
The best time to apply a mulch is probably late in May or early June.
Although a mulch will prevent light rainfall from entering the soil, it will facilitate the entry of heavy rains because it prevents the soil becoming capped by a rapid drying out on the surface. This maintenance of an open soil surface beneath the mulch also helps oxygen and carbon dioxide exchange and it prevents excessively high soil surface temperatures in hot weather.
An alternative to mulching is the frequent hoeing to remove all weeds, but this must be confined to a shallow soil layer. Deeper disturbances of the soil will increase the loss of water by evaporation.
Trees and Shrubs
In June there is a wealth of flowers, including laburnum (golden rain), magnolia, robinia, abelia, Buddleia globsa, cistus (rock rose), cotoneaster, cytisus (broom), deutiza, erica (heaths and heathers), escallonia, genista (broom), hebe, helianthemum (rock rose), hydrangea, kalmia, lonicera (honeysuckle), olearia (daisy bush), paeonia (tree paeony), philadelphus (mock orange), potentilla (cinquefoil), rhododendron (including azalea), rosa (rose), syringa (lilac), viburnum, clematis, jasminum (jasmine), and wisteria.
Pruning
At the end of June, or the beginning of July, when flowering is finished cut back the flowered shoots of deutzia, philadelphus (mock orange), ribes (flowering currant), genista and cytisus (brooms). Remove dead flower heads from rhododendrons and azaleas, ercias (heaths and heathers), laburnums (which have poisonous seeds) and syringas (lilacs).
New plants from Old
Layer low growing shoots of clematis and Chaenomeles japonica (Japanese quince) by pegging them with U-Shaped wires into peaty soil near the parent plants. Sever and replant when rooted.
Flowers
Use a sharp knife or secateurs and cut back to sturdy shoots lower down flowered stems of lupins, brunnera, doronicum and other early spring flowerers. Then a second show of bloom may appear.
Gather blooms regularly which are grown for house decorations to encourage plenty more to replace them. This applies to astrantia, buphthalmu, campanula, Chrysanthemum maximum (Shasta daisy) and many others that produce a succession of flowers.
Spray insecticide - one of the sytemic brands which stay with the plants' system for several weeks - to combat pests such as greenfly and whitefly that may be colonizing soft shoot tips or leaves and crippling growth.
Alpines
Prune back the seeding cushions of flowered aubrieta, iberis (candytuft) and alyssum, to leave a generous centre of new shoots to flower next year.
Carry on hoeing round larger plants not surrounded by mulches of stone chippings to remove bittercress which is an invastive annual that can quickly swamp the rock garden.
Dab deeply entrenched perennial weeds such as goutweed (also called ground elder), with a selective 'stick' weedkiller based on 2,4-D. This will kill off the entire root system without harming the rock plant with which it is too entangled to remove by forking out.
Bulbs
Dig up and dry off tulips and hyacinths whose leaves are yellow and 'spent' and store in a cool place for the summer, before replanting in early autumn.
Start mowing grass in which naturalized narcissi are now showing faded, brown leaves. This indicates that all nourishment from the foliage has been channelled to the bulbs and the leaves can now be removed.
Sprinkle a little balanced fertilizer at 120g per sq metre (4oz per sq yard) among summer flowering bulbs such as gladioli, acidantheras and galtonia, to spur the development of strong flowering stems.
Vegetables
June sowings can be made outdoors of French beans, beetroot, carrot, lettuc, marrow (and courgette), pumpkin (and squashes), radish, swede, sweetcorn and turnip. In addition this is the last time to sow runner bean directly in the open ground. These are gross feeders and the site on which they are to be grown should be prepared thoroughly, digging in compost or manure to the bottom spit of soil in a strip length of the row and 60cm (24in) wide.
Potatoes
The growth of early potatoes will now be well above ground, but they should be earther-up in stages to produce a wide flat-topped ridge. This ensures that any rain that falls on the crop will penetrate down to the developing tubers.
Thinnings
Many of the crops sown earlier in the year should now be thinned for the first, if not the second time, Thinnings from some crops, like carrots, produce useful variety for summer salads.