MARCH is the first month of autumn, a glorious time of the year.

As we move through the month the leaves will start to turn into their magnificent mantle of colour. Rich hues of golden yellow, burgundy and red with every shade in between.

March is an important time for pruning conifers, with the other recommended time being October.

Other smaller plants that change colour in autumn include Ceratostigma willmottianum or Chinese plumbago. Its Chinese name “Blue Snow Flower” refers to the cool, blue effect of its flowers in summer. This is a low-growing, deciduous shrub up to one metre with deep-blue flowers and a stunning display of autumn leaf colour.

Its rival in autumn colour is Vaccinium or blueberries. Some years ago, I recall seeing a hedge of Ceratostigma on a corner block in Curtin that presented a stunning summer flower display and equally so with autumn leaf colour.

SO, for a moment let us sidetrack to the second part of the Ceratostigma name, ie willmottianum. It is named after Mrs Ellen Willmott, a remarkable gardener in every sense of the word and a contemporary of that other famous gardener, Gertrude Jekyll.

The English family home of Warkley Place had a 13-hectare garden and the family were all keen gardeners. She inherited the home on her father’s death plus a substantial inheritance from her godmother. Willmott over the years developed the whole site and is thought to have cultivated more than 100,000 plants, employing 104 gardeners. She only employed men, once quoted as saying: “Women would be a disaster in the flower border”. Willmott used her wealth to fund plant-hunters to China and the Middle East including the famous Ernest Henry Wilson, who named this Ceratostigma after her, having discovered it growing in China.

She helped persuade her neighbour to purchase the site of Wisley in southern England, which became the Royal Horticultural Society’s Gardens, and donate it to the Society. Today, these gardens are a mecca for gardeners from around the world and even if you have time to see only one garden in England, visit the RHS Gardens at Wisley (see www.rhs.org.uk). Willmott with her extravagant lifestyle, owning estates in France and Italy, lead to serious financial troubles. She became increasingly eccentric and used to booby trap her estate to deter thieves and carried a revolver in her handbag. She died age 76 in 1934. Despite all this, we have to thank her for introducing hundreds of plants to decorate and enhance our gardens today.

SEDUM is a large genus of more than 600 species of succulents. One variety that has captured gardeners’ imagination initially in Britain and Europe and now becoming increasingly popular here is Sedum spectabile “Autumn Joy”.

The new growth starts in late winter with the appearance of tiny, delicate shoots that give the appearance of being killed by frost, but are impervious to frost.

Gradually through spring and early summer, the stems grow and in late summer the “flowers” form, resembling broccoli. Come autumn, these pale-pink flowers gradually change to deep pink and finally bronze. When the first frosts arrive, the stems are cut back to ground level and almost immediately the new shoots start appearing. These can be dug up and divided and are so, so easy to grow. Plant this sedum in bold groups for maximum effect.

In the autumn garden…

• With conifers it is vitally important not to cut back into the old wood. Most conifers will not grow back if clipped too severely.
• Evergreen hedging plants such as Viburnum and Photinia can, on the other hand, be hard pruned and will soon respond with new growth.
• Always try and shape hedges narrower at the top and wider at the base. This allows an even amount of sunlight and overcomes dieback at the base of the hedge.
• Pittosporum hedges need to be cut back softly, softly and not too severely at any one time.

 Tree quote

“The more slowly trees grow at first, the sounder the core. Such trees continue to expand with nearly equal rapidity to an extreme old age”. Thoreau, 1860.