How to Grow Crocus Thomasinianus



By Eric Larson, of Yale’s March Botanical Garden, for Garden Clips

Crocus Thomasiniana – the early, “squirrel proof” crocus.

March is all about Spring bulbs. It’s March thirteenth and I’m here in Connecticut crouching down amongst a big patch of Crocus thomasiniana which is a very early crocus. This is a very common color, the blue, purple with white as the petals get near the base. Crocus thomasinianus is also one of the smaller flowered crocus, two inches across. Some of the larger crocus hit three, three and a half, four inches across and with many different color selections.

Crocus should be planted in September, early October, in fairly well drained soil, you don’t want to put them in swampy soil, average garden soil is good. As far as sun exposure goes, crocus are very forgiving. Medium light shade, even full sun is ok. The bold initiates root growth in the fall and then sleeps in the winter, with this chilling requirements and then in the spring it sends up the leaves and flowers. The leaves on Crocus thomasiniana are only around until mid May and they don’t get very big. As the leaves are photosynthesizing and gathering sunlight for it to produce food to get through the next winter time it’s best to have light shade at best maybe full sun. What that means is you can grow many many crocus varieties, most crocus varieties, under deciduous trees, it’s alright for them to be shaded during the summertime after the crocus leaves die down. Oaks especially are later than many of the maples and as the late winter and spring sunlight penetrates to the forest floor it is a perfect environment for Crocus and the snowdrops and many, many other types of bulbs. It’s a great use of that space to create early spring color.

There are not many pests to worry about with Crocus but there is a serious one that we should talk about. Sciurus genus is the squirrel and they are death to crocus. They will dig them up, pull them up, they’ll eat the bulb and leave the flowers laying there. There are a couple things you can do. Crocus thomasiniana is the least susceptible to squirrels. They don’t seem to like the taste of that bulb very much so if you have a lot of squirrels, first of all I would try planting that. Second of all you can plant your Crocus drifts and cover them with chicken wire and then mulch to cover the chicken wire. I highly recommend this. This is working for us at the gardens, works for me home, and you will definitely not have the problems with the squirrels digging them up.

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