Gardening columnist JACKIE WARBURTON reports that, as autumn takes its toll on the leaves, Tree Week is getting close.

The autumnal colour on display in Canberra right now is spectacular as mature streetscapes planted over many years are in all their glory.

The liquid ambers, oaks and elms are dropping their leaves, and all these can be collected, composted and placed on to the garden over winter or early spring. 

The smaller the leaf, the quicker it breaks down. Keep that in mind if you’re looking for a shade tree. Plant it where the leaves fall into garden beds for ease of future maintenance and not over a path where they can be slippery. 

Autumn’s shorter daylight hours and cooling temperatures activates the abscission process and leaves will start to reduce auxins, change colour and drop to the ground.

Break up big leaves by placing them on the lawn and mowing over them. Pop them in the compost and turn it over, adding water when it’s dry. Over time, the material will become unrecognisable and that means it’s ready to add to the garden.

It can be put at the base of all plants, native or exotics, but don’t cover the stem.

For autumn colour, buy plants now when the colours are at their best. There are so many to choose from, but I wouldn’t recommend a tree over eight metres for a Canberra backyard garden. That height will keep it away from any future tree regulations.

Canberra Tree Week is from May 3 to May 11 and there are many activities in and around Canberra that display our tree history and stories of the region. 

All the events are available to the public. The main event for Tree Week is a dinner on May 7 at the Weston Creek Labor Club with a guest speaker talking about oak trees. For more information, contact Friends of the ACT Trees on sites.google.com/site/factacanberra.

ANY unusable space can become a garden to grow ferns, Acanthus and other shade-loving plants by changing the soil with good organic compost to mimic an understory of a forest and a little misting. 

If there is no direct sun on the plants, bright light is just as good. 

However, if there are too many shade plants, they can become leggy and will show they don’t like that space. 

Watering is different from a garden in the sun with frequent applications, but not large amounts at one time. 

Rocks can also be a good addition to this style of garden as they help to keep plants’ roots cool in the heat of summer. Decorative rocks are a low-maintenance mulch.

PRUNING of winter irises and hellebores can be done now. Remove all old leaves and clean out the crown of the plants to allow sunlight to access the base of the plant. 

Removing all the old leaves will take away any overwintering aphids and white fly that may be under the leaves and there will be more flowers in winter. 

Jottings

• Prune crepe myrtles as soon as leaves have dropped. 

• Sprinkle diatomaceous earth under roses to prevent hibiscus flower beetles. 

• Plant conifers before the soil gets cold.

jackwar@home.netspeed.com.au