THERE are few more stunning sights than the golden yellow leaves of silver birch (Betula pendula) against a clear, blue sky.
I planted silver birch at just one metre tall when we purchased our home in Watson in 1991; now they’re a magnificent 15 metres tall made more beautiful by the smooth silver of the flaking bark off the trunk. Their cascade of small leaves fall on to the garden beds to remain, rotting down to enrich the soil.
The huge leaves from the nearby Magnolia soulangeana need extra help to break down. I shred them using either the mower or a combination blower/vac. with inbuilt shredder – although it’s still good exercise sweeping/raking leaves off paths and driveways where they can be a slippery hazard when wet.
WINTER has arrived, at least on the calendar, but the serious frosts have been late with the result bulbs seem to be popping up early. We still need substantial rain even though, seemingly, we have had some good showers.
The question is: do we need to water the garden in winter? At present, the answer is a definite yes.
But how do we decide? My advice is “dig an ‘ole” of at least 30 centimetres in various places around the garden. This may seem a lot of trouble but even after 25 millimetres of rain, due to the dryness, this may have penetrated only 10-15 centimetres into the soil, which isn’t deep enough to reach the roots of most plants, particularly trees and shrubs. Obviously, this test depends on how well soil is looked after.
Another good test is to push a 30cm screwdriver into the soil; does it go in easily? If not, it may indicate compacted soil and subsequently a watering problem.
IT’S time to give many perennials a serious haircut; that is crew cut to ground level. I started at one end of the main bed with Echinacea or cone flowers, next peony leaves, followed by Canterbury bells (Campanula persicifolia).
Then cutting back the penstemons, of which I left about 20 centimetres above the ground.
Sedum Autumn Joy has now finished flowering and the long stalks with the dried flower heads will have turned brown and can be used for dry-flower arrangements. If not for this purpose, then cut them to ground level or simply pull them out if they are still soft. The new light green shoots will be starting to appear and continue to grow through winter. This is also a good time to dig them up and divide to fill in gaps in the garden or give to friends.
If winter iris (Iris unguicularis) has finished flowering reduce those long, strappy leaves to within 15-20 centimetres off the ground.
- This is positively the last warning to remove all sprinklers and nozzles from hoses or severe overnight frosts will destroy them!
- Look for the great collection of winter-flowering hellebores now in garden centres such as Olivia’s joy, Sophie’s delight and Ruby daydream.
- It is not too late to divide hellebores in your garden, but do it now.
- To treat Curly Leaf in stone fruits such as peach, apricot and nectarine spray with organic Bordeaux or Kocide in June/July. Then again 10 days later plus the ground under the tree.
- Trevor Rogers will talk about growing cacti in Canberra at the next meeting of the Horticultural Society, 7.30pm, Monday, June 17 at the Wesley Church Centre, National Circuit, Forrest. All welcome.