September is the time we see the nights rolling in, shorter days and generally a cooler climate. It’s not all bad news though, September is the lovely time we get to see all our hard work in the veg patch on the dinner table. A busier time in the edible garden for harvest, however, the ornamental garden takes a little back seat at this time of the year.
SOW- Sweet peas in the greenhouse or in a cold frame for early blooms next year. Other hardy annuals such as Consolida, Calendula, Centaurea, Limnanthes and poppies can also be sown in situ. September is a good time to plant new perennials, especially towards to end as the soil is still warm, but the moisture levels increase.
Pruning & dividing- you can keep your hanging baskets in good nick until mid-autumn if you deadhead, water and feed them nicely. Plants such as dahlias, delphiniums, and roses need to be deadheaded to provide colour well into September. Any fading perennials need to be cut back now and it’s a good idea to divide and tired looking clumps of herbaceous perennials like crocosmias and alpines.
Pest & Disease- Watch out for discoloured leaves on herbaceous plants, such as Chrysanthemum. This could be leaf and bud eelworm. Powdery mildew can still be a problem if a dry and warm September.
TREE AND SHRUBS
General maintenance- Soak drought-stressed plants as the weather becomes cooler and wetter because the soil will absorb and hold any extra water you give it. When the autumn dead leaves start to fall, clear them promptly as they can be a source of disease in the garden. Nice to use the leaves on the compost heap, however.
Pruning and training- Time to prune late-summer flowering shrubs such as Philadelphus and give evergreens a final shape for winter. Climbing roses can also be pruned once they have finished their flower. Cutting back side-shoots from the main branches to a couple of buds is a good idea.
Planning- Collect tree and shrub seeds ready for sowing next spring. Order mature or large plants now ready for planting in October or once the soil becomes damper.
Pest and disease- Saprophytic fungi pose to become a threat to garden plants. The honey fungus may be more common in areas of woody planting and harmless fungi often appears on lawns or mulch. Powdery mildew Can also be troublesome in warm, dry, Indian summer weather (we wish). This will most likely dry up once the rains arrive.
Mowing-Don’t mow as often in the autumn months and raise the cut heights as the growth slows down. This will help the lawn to get through the last of the warm, dry weather.
Feeding- You can harden your lawn up for winter by applying an organic autumn lawn feed. Do this after scarifying and aerating but before applying a top dressing.
Soil improvement- Sand top dressings are usually applied at a rate of 2kg per sq. m, working them into the lawn area with a stiff brush.
Planning- This is an ideal time of the year to created new lawns either from seed or turf.
Maintenance- cover the pond surface with netting to stop falling leaves from getting in. This debris in the pond can encourage the growth of algae and weeds eventually harming pondlife by ridding oxygen levels. Be sure to top up water levels when needed, particularly during warmer weather. Also, remove dead leaves from waterlilies as the foliage dies back. You can also divide the waterlilies now and all other pond plants for that matter to increase stock.
Damping down- becomes unnecessary as the month progresses and it is best to water earlier in the day to avoid cool night dampness. This could encourage grey mould (Botrytis)
Ventilate- During warmer days but reduce ventilation once the cooler weather sets in. Use blinds to keep the area cool, but reduce shading towards the end of the month as the light falls.