Every year, I receive emails from concerned gardeners whose bulbs have already begun to produce leaves early in the fall. This is highly unusual: other spring bulbs are out of sight underground in the autumn. They produce their leaves in the spring, just before or at the same time as they bloom.
Often novice gardeners attribute this growth to a hyacinth, but in fact it’s not a true hyacinth that is sprouting, but instead a rather special bulb: the grape hyacinth, Muscari armeniacum. It gets its common name from the fact that the flower spikes look vaguely like those of a hyacinth.
This bulb, along with a few other muscaris, is unique in that it begins to produce its foliage, a cluster of narrow leaves, in the fall when the temperatures begin to drop, often shortly after it’s planted.
These leaves then last through the winter (and if ever they are damaged by the cold, the bulb will simply produce replacements in the spring), then the grape hyacinth blooms come spring, like the other spring bulbs.
No one knows why the plant has a reversed season of leaf growth: it’s just one of those mysteries of Nature for which there is as yet no explanation!
Many of my supposed spring bulbs do this, but I’m in a warm climate in Australia. I can honestly say I’m not mad about it – I feel like the extra leafing provides more photosynthesis and mineral takeup via root growth, so the flower in spring will be better. Chincherinchee, Sparaxis, Ixia, Freesia. They seem fine.
Where I live, these would be called summer bulbs and have a different life cycle than the ephemeral spring ones. So, your’s are behaving normally.