I have eremurus bulbs in a pot. Every year they produce vigorous leaves but do not flower. I have brought them in for a dormant period; but, the following year, they still do not bloom. They are a dark leaf variety the blooms when I bought the plant, were pink.
Thank you for contacting Toronto Master Gardeners concerning your potted Eremurus bulbs.
Eremurus is an octopus looking perennial bulb with a central crown, that is clump forming with rosettes of basal leaves producing dense racemes of small star-shaped flowers on erect leafless stems in early to midsummer.
Leaves and flowers grow from a central crown from which the fleshy roots radiate giving the bare root an octopus like appearance. Without a central crown present it will not produce a flower spike. Check to see if there is a central crown or crowns in your pot.
They also do not like being crowded and may require repotting to a larger pot with fertile sandy, well drained loam being placed in full sun. If there are new Eremurus bulbs in your pot. They will require their own pot. Eremurus do not grow well or flower properly in pots unless you can find one large enough to accommodate the large rosette of roots. Attached below is a video by Monty Don on potting a Eremurus.
The fertilizer to use will need to be high in potassium during their growing season. Fertilizer’s N-P-K ratio — the proportion of three plant nutrients in order: nitrogen (N), phosphorus (P) and potassium (K). Use a fertilizer with a high third number e.g. 10-10-25.
The websites below will provide information as well:
U-tube video for repotting:
https://www.bbc.co.uk/programmes/p00frpm8
University of Illinois’ information on Eremurus bulb basics.