I have various kinds of allium plants sprouting up in my Toronto garden right now. They are overcrowding it and I would like to move many of them to a farmhouse garden in north Pickering ( 25 minutes north east of my Toronto home). Is it possible to dig them up and replant them at this time of the year? Is their chance of survival ( and blooming this year) fairly good? Should I wait another week or so to let the soil warm up a bit more? My Toronto soil if fairly clay-ish. The Pickering soil is excellent, some clay and a nice rich “composty” mix.
Dear gardener,
Thank you for this very timely question. I suspect you know that the accepted answer to your question is that you need to plant your allium bulbs in the fall, let them grow a full root system over the winter, and they will flower in the spring.
It is recommended by most authorities (including the Royal Horticultural Society), and my personal experience, to only move bulbs, including alliums, after they have flowered. In general, the RHS suggests that after about three years, the bulbs will start flowering less, and that is when they should be lifted, divided, and replanted.
But since I did find one source that thought you could move and replant your allium bulbs and still have them flowering this spring, let us continue.
Toronto Master Gardeners usually only references academic sources, but you may find this article interesting. The ShunCy site says that two varieties of alliums, Allium aflatunense or Allium sphaerocephalon are more suitable for planted in the spring. They also says that allium bulbs that have short growing seasons and are smaller bulbs are more easily planted in the spring. But ShunCy is based in Galveston, Texas, so although this is of interest, I am not sure you should follow this advice for our area.
That being said, gardeners are “Citizen Scientists”, so if you are leaving your Toronto home to move to Pickering, and do not want to leave your bulbs behind, why don’t you try moving them? Nothing lost.
Just an additional note: Since we still have below zero temperatures at night in Toronto (first week of April), my suggestion is that you wait until the soil has warmed up so that you can lift your bulbs without tearing too much of their root system, and can take as much of the root ball as possible. I might also lower my expectations about having a significant display of colour from the lifted and replanted bulbs this year.
I hope this helps, and wishing you a lovely spring and summer up at your farm.