September: colours and coolness

I have just come back from walking in the Yorkshire Dales.

Being further north and more exposed it is a wee bit cooler there but dramatically beautiful all the same. The first signs of autumn are very evident. The mountain ash trees (Sorbus aucuparia) are taking on that rosy glow that will attract the birds and the bracken is beginning to turn brown.

Acres of undulating, pinkish heather stretch out over the moors and the hum of wildlife reminded me of just how much activity there is at this time of year. Bees, fly-catchers, red kites and buzzards are looking for their daily food. 

Closer to home you might be enjoying the berries of the wayfaring tree (Viburnum lantana), the guelder rose (Viburnum opulus) or the swelling hips of the roses. There are always the blackberries to pick if you want to stray away from the sofa!

The key to enjoying your garden in September is getting the most out of the remaining flowering period of your plants and noticing the changes that autumn brings.

So here are a few pointers to help achieve this:

• Use a liquid feed for your hanging baskets and pot plants. A feed that is high in potassium will provide the main nutrient that boosts flower and fruit growth. Look at the label on the packet and that will tell you the proportions of nitrogen, phosphorous and potassium in the liquid feed. Avoid high nitrogen feed as that will boost green growth.
• Dead head (take off using your thumb and forefinger) all flowers that are 'over' in your displays. When it comes to Dahlias, Penstemons and other perennials then use a pair of secateurs (or hedge clippers if you are in a real hurry!) to cut them down to their larger leaf level. This will encourage a second flush of flowering.
• Keep watering. The days and nights might be getting cooler but there is often a lack of rain to keep the thirstier plants happy. Be particularly aware that the moisture loving Rhododendrons and Camellias are forming their buds for next spring and need all the help they can get.

General tasks that will set the garden up for the coming year are :

• Dividing herbaceous plants. Phlox, Hemerocallis (day lillies) and hardy geraniums can be lifted this month. Two forks pushed in back to back at a slight angle and then pressed together will split the plant. Don't worry if you end up with a few sorry looking chunks of roots. They can become the most impressive plants in time.
• Spreading mulch where gaps are appearing in the garden. This may be composted leaves and grass cuttings from you compost heap or well-rotted manure.
• Planting evergreens while the soil is still warm. With the on-set of the autumn and winter rains you will have less watering to do than if you planted them in spring. Give them a good drink now by saturating the plant hole and after you have planted them but be alert to dry spells in the coming weeks.
• Thinning out oxygenating and floating plants in the pond. If you leave the debris by the side of the pond overnight before adding it to the compost pile, the wildlife will be able to make its way back into the water.

You may want to consider starting again with your window boxes and hanging baskets by creating an autumn display. Going to a garden centre can give you an overwhelming choice of options of plants. Checking the height, the hardiness and the colour of the plants will help narrow down the choices but the key is to choose evergreens with contrasts in foliage and growth habits such as grasses and Heucheras.

On the other hand that may be all too much fuss. You may see all you need to inspire you just by going for a long walk in the countryside and marveling at what is already at hand.

Guelder rose (Viburnum opulus)