August Gardening.

While the list of gardening tasks for August is shorter than in many months, there are still ongoing tasks to perform in the garden. Your main concern will be ensuring an ample supply of water for your plants. Take advantage of any cooler days to take care of grooming and weeding. Weed control is also very important, because with the warmer weather and increased watering, weed seeds will germinate and grow faster.
If you are looking for perennials to brighten up your borders then look no further than Penstemons. They are one of the most valuable late summer-flowering perennials and, in all but the coldest winters, are easy and reliable. Their pretty colours and elegant habit allow them to blend seamlessly into the herbaceous border. You can plant them with roses, between daisies (asters, rudbeckias and echinacea) and weave through softly flowing grasses such as Stipa.
Penstemons are easy to grow in any fertile, free-draining soil in full sun or light shade and they will tolerate dry conditions once established. Removing spent flowering spikes helps promote a long season of flowering.
Hardiness can be a problem, although most are killed by winter wet than severe temperatures. Some varieties have narrow leaves and these prove the hardiest. Generally, the broader and fatter the leaves the more tender the plant. As an insurance policy against loss take cuttings in late summer or early autumn – using soft leafy shoots about 3in-4in in length. Trim each cutting below the leaf joint, removing bottom leaves, and place three cuttings in a 2-litre pot containing a half-and-half mixture of sand and compost. Place in a cold frame or in a sheltered place and pot up individually in April, to plant out in May or June.
Penstemons can become woody and leggy if they are not pruned annually. In autumn, limit wind rock and tidy up borders by cutting back by about a third, being sure to leave enough foliage to provide winter protection. Once the worst of the winter weather is over (usually in late April) trim again to tidy; until then old stems provide valuable frost protection for the new shoots.
My favourite varieties are: ‘Blackbird’ (deep-purple), ‘Raven’ AGM (black-purple), ‘Osprey’ (white and soft pink), ‘Garnet’ (deep red) ‘Snow Storm (white with a tinge of pink) and ‘Sour Grapes’ (greyish blue).
Top Tips for August:
• Keep bird baths topped up with clean water, if hedgehogs visit your garden put a saucer of clean water out for them too.
• Camellias and Rhododendrons should be well watered at this time of year to ensure that next year’s buds develop well.
• Cut back herbs now to encourage a new flush of tasty leaves you can harvest before the frost.
• Divide clumps of Bearded Iris now so they have time to form roots and flowers buds for next year before the cold weather arrives.
• Take cuttings of tender perennials such as Pelargonium and Osteospermum.
Whatever August brings, I hope you are able to enjoy some time relaxing in your garden, or visiting others for inspiration.
Rachel Sobiechowski, P&R Garden Supplies, Fengate Drove, Brandon, Suffolk, IP27 0PW

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