July Gardening

July is often the hottest month of the year and it’s important to water the garden thoroughly once or twice a week rather than little and often as this encourages plants to put down roots in search of water rather than coming up to the surface. Containers and hanging baskets need watering every day and sometimes even twice a day if it is hot and windy. The plant of the month for July is Hydrangeas. Hydrangeas are a vast group of plants ranging from climbers, trees and shrubs. The most popular are mophead and lace-cap hydrangeas, and these have the unique ability to change flower colour in different soils. This colour change is due to the soil pH which affects aluminium availability. Those with blue or pink flowers tend to be blue in acid soil conditions (high available aluminium levels), mauve in acid to neutral soil conditions, and pink in alkaline conditions. White flowers, and also green-flowered cultivars, remain white or green regardless of soil pH. You can replicate the necessary soil pH by planting blue hydrangeas in pots of ericaceous compost, and watering with a hydrangea colourant once a fortnight. The ‘old wives tale’ of using rusty nails when planting hydrangeas is false, as the colour is due to aluminium not iron. Use rainwater, as mains hard water can affect the flower colour, turning blue flowers mauve or pink. To enhance red or pink flowers, apply a dressing of ground lime in winter.

Hydrangeas thrive in a moist, but well-drained soil, in a cool, semi-shady part of the garden. Try to avoid exposed east-facing sites, where cold winds may damage young spring growth, and also avoid dry, sunny spots. On lighter, sandier soils work plenty of organic matter into the soil before planting, and in subsequent years apply organic matter as a mulch. This could be well-rotted leaf mould, garden compost, or farmyard manure.

Hydrangeas flower from mid to late summer on the previous year’s growth. Dead blooms should be left on the plant (not deadheaded) over winter to provide some frost protection for the growth buds below. Remove the dead flowerheads in early spring, cutting back the stem to the first strong, healthy pair of buds down from the faded bloom.

Often Hydrangeas can be found in flower from late March onwards in Supermarkets and Florists. These hydrangeas are known as ‘Florist hydrangeas’ and have been forced into flower to make gifts for holidays such as Valentines day or Mothering Sunday. Forced hydrangeas are usually grown for a one-time, spectacular show. The plant has been fed specifically to produce many large blooms quickly, quite often at the expense of the future heath of the plant. In addition, the hydrangea chosen for this purpose are grown in greenhouses should be treated as houseplants, as the soft shoots will be killed by frosts or cold temperatures. They can be planted outside once the risk of frost has passed in early June. Top Tips for July: • Prune Wisteria now. Remove the whippy side-shoots from the main branch framework to about 20cm from their base (about five leaves from the main stem) • Dead-head bedding plants and perennial plants to stop them setting seed and to encourage further flowering. • Apply a high-potash fertiliser once fruits start to form on peppers, cucumber and tomatoes. • Check for cabbage white butterfly eggs under brassica leaves and treat accordingly.

Whatever July brings I hope you get a chance to step out into the sunshine and enjoy the season as you tackle this months gardening jobs. Rachel Sobiechowski BSc (Hons) P&R Garden Supplies, Fengate Drove, Brandon 01842 814800 www.p-rgardensupplies.co.uk