Astilbe Amethyst Roots
I was wondering at what time of year I should plant them.
I should also add that you can start them earlier by placing in pots with a good commercial potting mix.
They can be placed in a cool greenhouse or a cold frame. You will need to keep them in bright light but above freezing temperatures.
You can then plant them out when weather warms.
Plant out any time after danger of frost has passed in the spring.