Your Garden in August
By John Dunster
Powdery Mildew and Rust
Both powdery mildew and rust are different species of fungi which infect plants at this time of year. The white coating and powder on leaves is caused by a fungus with the unusual feature of high water content in its spores so it can infect foliage in dry conditions. Plants most infected are acers, clematis, daises, dephiniums, lupins, phlox and sweet peas. Combat it by watering the plants well (but only their roots) spacing them out to give good air circulation and destroy infected leaves promptly. Fungicides are available but need to be applied before the plants become infected and repeated several times
There are many types of rust disease all caused by different species of fungi affecting garden plants, each rust attacks only a small group of plants, so for example it won’t spread from hollyhocks to roses. The following plants susceptible to rust are chrysanthemums, hollyhocks, fuchsias, pelargoniums, alliums, peas and roses. Avoid over use of nitrogenous fertiliser, bin dead material and water carefully but do not let it deter you from growing these plants. When buying plants that can be infected with either of the above diseases always look out for cultivars bred for resistance
Sowing Vegetable Seeds
There are quite a number of vegetables that can be grown at this time of year which can be harvested during autumn and winter. You can sow seed directly into the ground now or raise new plants in modules to fill gaps after harvesting summer crops. Just rake over the surface of the soil, make drills and water the base of each one before sowing the seeds. Water again in a week if necessary. Some vegetable seeds to consider planting now are chard, packchoi, rocket, spinach, turnips, carrots and kohl rabi.
It is important to keep dead heading to ensure a continuation of flowering especially dahlias. There are two things to be careful of when deadheading dahlias. The first be sure of the difference between an unopened bud and a spent flower. They can look quite similar, the difference being that the spent flower is always conical whereas a bud is either round or button shaped. The second important thing is to follow the stem of the spent flower right back to the next leaf and cut just above it.
Cut Price Plants
At this time of year garden centres may well be selling off plants at reduced prices to make room for their autumn and Christmas stock. If you are prepared to take a chance some of these offers can be real money savers. To revive these plants give them space, and if the compost is dry submerge the pot in water until no more air bubbles appear. Some plants may be strong enough to plant out straight away but others may need repotting into a larger pot. Trim off any dead leaves and give it a liquid feed regularly until the end of September.
As the month progresses more fruits will steadily ripen, high potash feed will help this. From now on the aim should be to develop as much fruit as possible and not encourage actual plant growth by cutting off the tip of the plant and removing the leaves around ripening fruit.
Pest and Diseases
Keep an eye open for caterpillars on brassicas and blight on potato foliage. If potatoes become infected it is best to remove the foliage completely cutting it down to ground level.