Since I'm in Vancouver, some of the annuals in my containers sprout again the following year.
I also have perennial plants and bulbs in some of these containers.
How do I deal with these in regards to putting fresh soil in the pots? Is it necessary?
Or can I simply continue to give them liquid fertilizer?
With shrubs, trees, perennials and anything that stays in a container for long periods, topdressing in spring is the best practice.
That is, you remove the top inch or two of soil and replace it with something quite rich like compost, or potting soil mixed with a little fertilizer.
With your annual/ perennial containers, you would then go on to feed liquid fertilizer through the summer in the usual way.
But container trees and shrubs usually outgrow their pot after a few years and need a totally fresh change of soil and a bigger pot.
This can sometimes be postponed for a few extra years by doing extensive pruning of the top growth.
But eventually a soil change is necessary.
If no bigger pot is available, root-pruning, and top-pruning are needed so that the trees and shrubs can fit into the old pot along with the fresh soil.
With annual/perennial containers it's also best to repot in all-fresh soil every few years because perennials and even returning annuals ultimately fill all the available soil with roots.
At that point, they'll need extra space or division.
Anne Marrison writes about gardening for The Record and sister paper, the Burnaby NOW. She is happy to answer garden questions. Send them to her by email, firstname.lastname@example.org.