Fragrant plants, such as lavender, and oil-containing plants can be composted.
Dear Anne,
Should I put smoke bush leaves in my compost? When I prune the branches, there’s quite a smell of resin and I’ve read you shouldn’t compost leaves with a high oil content. I dry leaves on trays in my basement to give me a supply of carbon to compost through the winter.
Donna Crosby, Coquitlam
The leaves of many aromatic plants contain essential oils in tiny amounts, including herbs such as mint, thyme, etc. But I have never come across any suggestion aromatic plants should not be used in compost.
I’ve composted herb and aromatic prunings for years along as part of a general mix for composting and had no discernable problems.
Since you can spread your leaves out on trays, it sounds as if you don’t have a large quantity of leaves anyway. I’d say go ahead and compost them.
The only caution I might make is that a well-run compost should have as wide a variety of components as possible. These could be: leaves, grass-clippings, soil, weeds, manure and clipped prunings. The idea is that no ingredient should dominate.
It’s not impossible that compost with a huge quantity of aromatic leaves and not much of anything else could cause problems for the worms, slugs and friendly bacteria that help decomposition. After all, in past centuries, aromatic leaves were used to deter ants, fleas, etc. from gaining access to a house.
There certainly are leaves that can slow down composting by being reluctant to disintegrate (beech and some oaks, for instance).
Black walnut leaves contain juglone which is toxic to many plants. Many gardeners won’t compost them – although others say black walnut leaves are fine if you compost them by themselves for a year before adding them to a general compost.
Dear Anne,
How do I preserve hawthorn branches so the berries stay on them and remain attractive until Christmas? I have had two suggestions so far: cut them and store in a cool dry place in a burlap sack or spray them with varnish.
Do you have any suggestions?
David Patching, Ladner
The traditional way of keeping berries on decorative boughs is to mix one part of glycerine to two parts of boiling water. Then hammer the end of each stem until it is crushed and put the stems in a tall vase for a month to six weeks. My vote would be for six weeks.
It’s best if the room is dark and cool.
If the liquid level starts going down, add one part of glycerine to three parts water. An anti-dessicant spray is also supposed to keep the leaves and berries from drying out.
Dear Anne,
I have five hostas in six-inch pots. Can I keep them in pots over the winter until I know where to put them?
I can stand my pots in some tall, empty containers to give them some protection from the elements. Will that help?
Irene Brown, Ladner
Yes, you can keep your hostas in pots over the winter. Hosta plants are extremely hardy. The tall, empty containers would help protect them, especially if you surrounded the inner pots with an insulating layer of leaves inside the tall containers.