The changing of the season with deciduous trees is seen by some as a time of great beauty; for others it’s a messy time in the garden. Then there are those who see it as a window of opportunity.
Deciduous trees make fantastic additions to the garden and in recent years there have been some real stand-out varieties making their mark in WA.
The surprise package of the lot for me would be the sugar-red maple hybrid Acer x freemanii, Autumn Blaze, and the red maple Acer rubrum PNI 0268, October Glory. These two trees have proven to grow exceptionally well in Perth and the South West and as trees mature the autumn colour show they put on is simply dazzling.
I have marvelled at the golden hues initially put on by my three and four-year-old trees before they turn crimson red and eventually drop their foliage in a sea of colour.
This bed of colour is the window of opportunity for people who want to improve the quality of their soil; effectively these leaves are the gold that those who see these trees as messy can’t see. When collected and composted, either formally through a bin or informally through large piles in garden beds allowed to compost down, they make amazing high- quality compost that is home to trillions of microbes.
Deciduous trees come in many shapes and forms. Among my favourites is the beautiful Forest Pansy Cercis, with its amazing autumn coppery foliage, red spring foliage, pink late winter/early spring flowers and 4-5m maximum-height growth habit.
Another is the gorgeous Chinese tallow tree, with its golden but sometimes crimson foliage set atop a 4m-high tree which colours up in coastal locations and warmer climates and is relatively drought tolerant.
One recent introduction from Olea Nursery, in WA’s South West is Alford Blaze Platanus orientalis.
This variety of plane tree has thick, leathery, deep-green leaves which transform into the most amazing, fiery autumn colouring in shades of deep orange, bronze and red. Its colouration is not determined by cold as such so the colour is something you can rely on each year. The stunning display continues for a long period over autumn and into early winter when other plane trees are either still green or turning to the usual brownish, gold shades. Best of all, this tree is a third of the physical size of the traditional oriental plane tree, making it ideal for medium-sized gardens.
The important thing now is to identify what trees you like, secure them early from your local nursery and get the soil ready to plant as soon as they go dormant.
Autumn lawn tips
Autumn is also lawn-renovation time, either getting it back on track or in some cases replacing it altogether.
Lawn renovation is always a contentious issue, particularly whether to vertimow or core.
Vertimowing or dethatching involves blades ripping into the surface of the lawn, which works well for rhizomatous grasses such as couch, Zoysia grass and kikuyu.
The problem with this form of renovation is the stoloniferous buffalo grass, which does get heavily thatched if it’s fed high nitrogen-based lawn fertilisers. Buffalo grass varieties are, in my opinion, best cored and top-dressed with organic humus such as that made by local company NutraRich, which produces a specialised product, Turf Topper, a soil improver and organic fertiliser in one.
Vertimowing followed by top-dressing can produce amazing results in old couch lawns.
Now is also when you need to take action to avoid prickles, weeds and patches in your grass.
Having lawn sprayed with a pre-emergent herbicide will knock weed seeds out before they smother your slow-growing winter lawn.
Top-dressing with a purpose-designed, humus-based lawn top-dressing will improve the soil’s health, the turf’s growth and cover patches before weeds can germinate and get hold as the weather cools.
Time to repot
Another major task to tackle at this time of the year is repotting, something many forget is important — particularly if you haven’t done it for a couple of years.
The average potting mix will sustain a potted plant for 12-18 months but after that it’s pretty much sand and roots. At this point applying fertilisers is critical or the plant will sink into decline.
The classic indication of a plant ready for repotting is when they lose density of foliage as the soil can no longer sustain the amount of foliage, leaving them looking haggard and tired.
The main decision is what soil to replace them with. I’ve noticed a trend recently for some retailers to promote cheap potting mixes.
Quality potting mixture is the foundation of success in the garden and they are developed using a tremendous amount of science. Understanding the plant’s roots, air needs, the moisture-holding capacity of ingredients, drainage capacity and the nutrient levels required to sustain the plant’s growth over a six to 12-month period are all criteria used to determine optimum results, so seeing cheap mixes gets on my nerves.
Always look for a quality potting mix. If a product bears the Australian Standards red box, and costs more than $10 for a 30 litre bag, you’re likely getting a quality mixture.
Companies such as Scotts and Baileys provide quality potting mixes, originally developed in commercial nurseries who cannot afford failures.
