Summer Gardening Tips
PUBLISHED: 09:00 15 July 2014
Griselda Kerr concentrates on pruning and feeding tasks that might be carried out in the garden this month
The hard labour of gardening surely belongs to other seasons? July is the month for secateurs and scissors, not choppers and chain-saws. If you spent every evening just deadheading and snipping herbs you would surely have done well for your garden. There are even so, other things that can usefully be done now.
PRUNING: Stoned fruit (peaches, damsons, plums, gages, apricots) are best pruned on a hot summer day being vulnerable to silver leaf. In fact, this applies to all members of the Rosaceae family so if you have work to do on any sort of prunus, such as flowering cherries, do it on a hot dry summer’s day as pruning cuts are least likely to get infected at this time of year. Apples can be given some further pruning now, even though the major work is done in winter – you can remove lateral growth, cutting off new wood to about 6–8 buds. Espaliers can be pruned hard at the end of July so that young fruit is exposed to ripen in the sun. Having pruned, water and feed with fish, blood and bone and mulch.
Staying on fruit trees, apple trees benefit from their fruit being thinned by mid July. To get good full-flavoured fruit, it is highly recommended to take out all but one or two fruit from each cluster of apples and pears and thin out plums to about 3” apart. This stops the tree becoming exhausted, prevents it becoming a biennial bearer and stops branches breaking under the weight. Do not forget to cut down the fruited canes of summer raspberries when they are finished, it being easier now to see which were the fruiting canes.
There are one or two other trees that call for pruning in mid-summer. Magnolia is one: it is preferable not to prune them at all but if one has outgrown its allotted space, now is the time to cut back. Sophora needs pruning now to avoid bleeding sap. Birch trees look better if their lower branches are pruned off when young to obtain a smooth clear trunk but this again needs doing in mid-summer to avoid bleeding sap. Walnuts are traditionally pruned on St Swithun’s day (15th July) as they approach the end of their growing season and figs need their tips pinching out to encourage bushy growth. If you have a leylandii hedge and only want to trim it once, now is the time to do it.
Evergreens such as bay, varieties of euonymus, Elaeagnus x ebbingei and box will repay regular clipping. If box looks rather orange the roots may be dry and cannot draw up the potash needed for healthy colour – a sprinkling of VitaxQ4 at its roots, watered in well, helps greatly as does a mulch to maintain moisture. Hedges that have got untidy like hawthorn, beech, hornbeam, Berberis thunbergii and yew can be clipped now (and again in October). Yew is traditionally clipped in August but a clip now will make it worth cutting again in October before winter sets in.
Shrubs that have finished flowering, such as deutzia, escallonia, philadelphus, kolkwitzia, snowberry, olearia and weigela, will need pruning if they have not already been tackled. Taking out ¼-1/3 of the oldest stems from the base (on mature plants that is) and cutting other healthy flowered stems back to a strong bud to achieve a good shape is the usual instruction. If you snip off the faded blooms on Buddleja davidii you will get another flowering emerging beneath the old flowers. There are other shrubs that just need a haircut – evergreen ceanothus is a classic example where old wood must not cut into: others include Convolvulus cneorum, varieties of hebe and cistus. They will hold their shape, last longer and flower better with this care.
Climbers and wall shrubs that flower on the previous year’s shoots will need pruning. Japanese Quince (Chaenomeles) and Prunus mume (Japanese apricot) for example, will flower better next year if pulled into the horizontal and spur pruned now, with unwanted shoots removed. Pyracantha too can be clipped hard into shape. Dead heading, by shortening the flowered stems of large flowered clematis, now almost over, will encourage a second flush in late summer and early autumn. If you keep clematis well watered and with an occasional liquid feed they will outdo themselves later in the year. As your rambler roses finish flowering, this is a good moment to cut out one or two long leggy shoots from the bottom to divert growth into new shoots for next year.
Then there is the fun of pruning perennials for some fresh green growth: cut aquilegia right down after they have finished flowering – they will clump up even better next year. Astrantia, if cut down now should give you another flowering. Gaura lindheimeri can be cut back in the middle of its growing season and it will return looking fresh. Geraniums, the spreading daisy Erigeron karvenskianus, nepeta, heleniums, salvia, anthemis – indeed almost any perennial that is looking tired will leap back into fresh growth if given encouragement.
FEEDING in mid-summer with a fast-effective liquid fertiliser – Tomorite or any high potassium fertiliser – is very helpful to some plants, particularly those about to enter their main flowering period like dahlias, canna, abutilon, lilies and eucomis or those like roses, that have had their first flush and are getting ready to go again. An application of Top Rose now would do them very well. General fertilisers also have a part to play. From the end of July an application of one oz. per square yard of, eg. Growmore, Nutra Allround Plus (Nutra Allround Micro on ericaceous soils) or another general purpose fertiliser, will help your soil support flowering plants. There are places where your broadcasting of fertiliser should skip a patch: over Mediterranean plants that like it tough, lavender, silver/grey leaved perennials, cistus, salvias, perovskia, helichrysum, over herbs, succulents, annuals and ericaceous plants. But these apart, it is a perfect time to feed the soil, provided it is not bone dry. Pots, containers and hanging baskets benefit from a regular feed of any high potassium fertiliser and acid loving plants will improve their autumn colour with a regular feeding of Flower of Sulphur. Late summer vegetables like courgettes benefit from a high nitrogen feed now.
Watering: It goes without saying that watering pots at this time of year is an essential routine for new plants and plants in containers. Plants that are forming buds now for next year, such as Camellia and Wisteria, benefit from water in July and August. Water in the early morning and evening to avoid evaporation and leaf burn and water thoroughly or not at all – a sprinkling will encourage roots to turn towards the surface and be scorched. A thick mulch applied after watering will help keep the soil moist. It is a matter of concentrating on where the need is greatest and, as with all things in the garden, leaving time to relax and enjoy what you have created. n