The autumn garden has arrived

“I cannot endure to waste anything so precious as autumn sunshine by staying in the house” — Nathaniel Hawthorne

After such a long and dry, warm spell our gardens are welcoming with open arms early autumn rains. The rain is refreshing our gardens, and they in turn are beckoning us into them. It’s time to get organised ahead of winter, and there’s plenty of variety on the gardening front. The still warm soil encourages root growth in new plantings, ahead of winter. In some ways this is the best season for sowing seeds, planting new trees, shrubs and seedlings.

Delightful Dahlias

Summer may be behind us but there are still many flowers to enjoy. March is the month for dahlias. Dahlias are currently at the pinnacle of their powers, and simply quite stunning. In spring I was lucky to be gifted some dahlia tubers, and they’re now happily flowering alongside my bedding dahlias. 

There are many reasons to plant Dahlias in your garden

Dahlia flowers from Judith van Boxel’s garden are perfect as cut flowers

It’s very exciting being rewarded with beautiful, new coloured blooms. Like many other plants, they will need some care and attention, especially if I’m to be rewarded again with more flowers next summer.

The Autumn garden make-over

For want of better words, our gardens can start to look a little tired and shabby in autumn. Pruning helps encourage plants to be less woody, and have more flowers. First up, remove any dead, broken or diseased stems or branches. As a general rule of thumb prune flowering plants back by around a third, aiming to cut back to signs of green growth. It pays not to be too tough in autumn as the colder winter temperatures and wind have yet to arrive. You don’t want to shock your plants and discourage new growth.

There are always exceptions to the rule. Not all plants like, or need to be pruned back in autumn, and prefer spring pruning instead. Some have striking seed heads or provide food for birds. These include: Echinacea (Cone flower), Rudbeckia (Black-eyed Susan), Siberian Iris and Helleborus (Winter Rose). Older foliage helps protect new spring foliage, and by not pruning you’re also not stimulating new growth in time for winter. Chrysanthemums should be pruned after frosts, and ornamental grasses just before new spring growth appears. Plants like Delphiniums, Hollyhocks and Dahlias should be left to die down naturally. This encourages self-seeding and helps provide energy for the next season’s growth.

Some plants bloom on older wood, or develop buds later in early summer. If you prune in autumn you are potentially removing future flowers. These include; Azalea, Dogwood, Forsythia, Deutzia, Philadelphus (Mock orange), Weigela, Lilac, Magnolia, some Hydrangea like the Oakleaf, and Rhododendron.

The excitement of planting a new deciduous tree

It’s an excellent time to plant trees for autumn colours. Deciduous trees are a favourite of mine. Here in Kapiti we are spoilt for choice with a number of medium to large deciduous trees that put on quite the show of brilliant golds, oranges and reds. There’s nothing like a deciduous tree to remind you of the change of seasons. It’s so encouraging seeing the burst of fresh new leaves in spring. They also provide shade in summer, and when we need more light in winter they helpfully shed their leaves. Their leaves then provide us with mulch for our gardens. I am definitely a fan!

If you’re not quite sure what deciduous trees are best for you, a leisurely stroll around your neighbourhood streets and parks will help you choose. Some of my favourites include; Liquidamber (Sweet Gum), Gingko, Crabapple, Acer (Maples), Claret Ash, Amelanchier (Service Berry), and Parrotia (Persian Ironwood), We enjoy favourable growing conditions, so there’s no need to feel you need to buy an already large specimen tree. I’ve found small to medium trees appear to establish and grow faster.

Autumn foliage of the Ginkgo biloba – widely known as a living fossil

This month’s gardening gems:

• trim hedges, big and small

• sprinkle Epsom salts around vegetables, roses, citrus and shrubs for growth – readily available and cost-effective

• plant winter seedlings: vegies - lettuce, brassica (cabbage, turnip, radish, kale, bok choy, cauliflower, broccoli, brussel sprouts); flowers – Dianthus, Pansy, Cornflower, Hollyhock, Larkspur, Lobelia, Poppy, Scabiosa, Snapdragon, Stock, Sweet pea, Viola and Wallflower.

• spray fruit trees with an organic spraying oil to help control scales and mites, and a liquid Copper fungicide to control leaf curl, leaf spots, black spot and downy mildew.

• rake up falling leaves and put straight onto garden as a mulch

• pick-up and dispose of fallen fruit, especially if it’s diseased or has pests (Codling moth)

• shake seed heads over the garden for new seedlings: parsley, coriander, carrots, sunflower, spinach and poppy to name a few

• divide up and lift perennials: Dahlias, Begonias, Hostas, Geraniums, Penstemons and Lavenders

• collect up and dispose of fallen diseased fruit.