This is the time of the year when many annuals are well into their stride, but few perennials are at their best. However one group of plants that comes into its own is the phlox. With a wide range of pastel colours and rich, distinctive fragrance, they have become classic summer plants and are greatly appreciated by a large number of gardeners.
Phlox originated in North America, in the late 19th century British nurserymen started to select and cross breed to produce the wide selection of varieties that are available in garden centres today. Many of today’s varieties come from the original wild variety Phlox paniculata. Pink, often with a dash of lilac or mauve, is the most common colour of the paniculata varieties, with an average height of 3 feet.
Although easy and rewarding to grow, phlox are not entirely trouble free and will not live forever without some care and attention. A fertile soil that is moist but not waterlogged is ideal. Lack of moisture puts the plants under stress, which can result in mildew becoming a problem. The problem can be reduced by planting phlox in an open airy place so there is good air circulation around the plant and keeping the roots cool with a mulch. After flowering, the plants should be dead-headed, which can often result in a second flush of flowers in the autumn. They are ideal for cutting with their long stems and pleasant fragrance. Most varieties do not need staking because the stems are quite strong. Taller varieties can be kept tidy by cutting them back to about one foot tall in June or pinch out the growing tips. This will encourage bushier growth and sometimes produces a longer flowering period.
Most phlox varieties deteriorate after three or four years, their flowers become smaller and the clumps less vigorous. It is possible to encourage them to produce good blooms for a number of years by thinning out the weaker shoots in late spring when they are 6-12 inches tall. Digging up and dividing the clumps during the winter is more beneficial because it will produce rejuvenated plants. Divide the clump, discard the dead part at the centre and replant the outer parts of the clump in soil enriched with well rotted compost. Eelworm is a problem on some soils that will eventually kill the plant. Affected plants should be dug up and burnt, phlox should not be grown in the same ground for at least three years.
Phlox paniculata ‘Mount Fuji’ is a late flowering variety that produces large pure white flowers in September. Phlox ‘Eva Cullum’ is a well known variety with deep pink flowers. Phlox paniculata ‘Norah Leigh’ is a variegated form with a white border around the leaves and pink flowers. There are several dwarf phlox, like phlox douglasii, that are suitable for dry and sunny rock gardens or an alpine trough. It forms a tight mound with small, stiff leaves and flowers from spring into summer.
Newly planted trees and shrubs will need to be watered in their first year of growth to establish a good root system. When planting in spring or autumn dig in lots of compost into the planting hole and place a mulch of compost or manure or bark around the plant while the soil is wet to seal in the moisture in the soil. Sink a pot or plastic bottle into the soil near the plant so water can be applied directly to the roots when it is needed in the first year. Using a sprinkler or hose to water your plants is a waste of water. Most of the water will evaporate off the ground before it reaches the roots. Use a watering can to apply the water to the roots and water in late evening or early morning. Collect rainwater from the roof of houses and store in barrels or tanks, water buts are available with a tap. Collect grey water from washing machine and baths, place a plastic bowl in your kitchen sink to collect washing-up or rinsing water and use it directly in the garden. Once plants have established themselves after this first year there is less need to continue watering and they will safely survive dry summer periods.
Jobs for the Week
For those with vegetable patches or allotments the coming weeks will provide you with surplus of provisions which need to be harvested and stored or preserved to ensure best return for your gardening investment. Any potatoes left in the ground can now be dug up and stored in the short term, make sure to turn over the potato patch to make sure you haven’t missed any and a good tip to keep potatoes fresh is to keep an apple or an orange in the bag with your harvest. Other vegetables coming into final growth include peas, cucumbers, carrots, cabbage, beans and beetroot depending when you planted them. One word of caution, potatoes can appear unblighted when being harvested but plant stems could still carry disease so it best to keep them separated from your compost heap.
As some of the bloom of July starts to fade it is worth pruning back dead heads on flowering plants throughout the garden.