September- is an excellent time for planting!
Updated: Sep 4, 2020
September is an excellent time for planting as the soil is still warm but moisture levels are increasing, which makes perfect conditions for plants to root.
Trees and Shrubs
This is the perfect time to plant and move shrubs and trees without having to worry excessively about their survival and establishment. Provided the soil does not dry out, they will get off to a flying start next spring as they will have had all winter to settle in.
Finish trimming evergreen hedging this month to make sure they are in shape for winter. Remember to cut edges slightly narrower at the top than the bottom, this makes them less liable to snow damage in winter and stops the hedge from shading itself out at the base, which can lead to dead patches.
Continue to dead head roses to prolong flowering into Autumn. Roses can show signs of black spot, so to prevent the spread, clear up the fallen leaves under the plant and destroy them.
Jasmine officinale is best pruned just after flowering, in late summer or early autumn. This gives new growth time to mature and flower early next season. It tolerates hard pruning and can be cut back to within 20 inches of the base.
Continue to deadhead summer-flowering plants to prolong their displays and provide colour well into the autumn.
Once they have finished flowering, either cut them down to tidy your borders or if they have good looking stems and seed heads, leave them in place for winter interest.
You can also lift well-established clumps, or any plants that are starting to go bare in the centre now, and divide them to make new plants and reinvigorate them and improve flowering and overall shape for next year.
However, there are a few perennials that are best left until spring, these are plants that flower later in the year such as asters, rudbeckias and grasses.
Autumn is a major time for lawn care, to get it back into shape and get it ready for the winter weather.
Kill moss in lawns with a suitable moss killer.
Rake and scarify the grass to remove dead grass, thatch and other debris.
Aerate compacted soil – especially clay soil – with a garden fork or a hollow-tine aerator.
Feed the lawn with an autumn lawn food to build up its strength and harden it for the onset of colder weather.
Now is a great time to start new lawns from seed or turf.
Repair bare areas or those with a thin grass covering using grass seed or a lawn patching kit.
Cover ponds with netting to prevent leaves from falling into the water where they will decompose.
Trim back pond plants and remove dead or dying leaves.
Reduce the amount of food you give to fish as they become less active.
Plant spring-flowering bulbs, such as daffodils, crocus, scillas and hyacinths in the ground and pots now. Leave planting tulips until November to reduce problems with tulip fire.
Keep deadheading summer bedding and hanging baskets but if they are past their best it is time to start planting winter and spring-flowering bedding.
Vineweevils are a gardener’s nightmare! check containers for vine weevil grubs, the “C” shaped creamy fat larvae can be a serious pest. Sudden wilting of plants is a sign, especially on heucheras in pots. Now is the time to treat them with a biological control – a parasitic nematode called Steinernema kraussei available from Nemasys.It can be very affective to be applied just after the grubs hatch but before they are large enough to cause much damage.