Planting a Rare Gladiolus Species Collection

Since I am getting bored with some of the plant collections that I already have in the greenhouse, I have decided to add a few more, since there is nothing as fun as discovering a new genus, for the curious mind rarely rests. I decided to add a small collection of gladiolus species, wild forms of the fancy big hybrids you are all familiar with.  Gladiolus species are hard to find,  and only a few retail mail-order nurseries sell them, ( mine came from Telos Rare Bulbs in California). These are simply not the sort of bulb (corms) one will find in an ordinary bulb catalog, they are true collector plants.

The genus Gladiolus is large, so if you imaging in your head the more fancy ( or more common) frilly, tall lush Glad’s one sees in funeral sprays and church arrangements, think again. Like much of nature, there are many species all within the same genus, and the genus Gladiolus is no exception, with over 255 species which all grow in the wild in Africa, Madagascar, Europe and the Middle East. The ones I am planting are winter-growing South African species, which are more delicate, almost orchid-like blossoms on smaller plants, growing from 10 inches to 20 inches tall, in most cases. Perfect for small pots. If you are interested in learning more, check out the Pacific Bulb Society site for more images and cultural info.

I use a few books as reference, mainly  Spring and Winter Flowering Bulbs of the Cape by Barbara Jeppe, and The Color Encyclopedia of Cape Bulbs by Manning , Goldblatt and Snijman.

And this book, which I brought from a mail order source in South Africa, which has been very helpful.

Species gladiolus are perfect bulb plants for cool to cold greenhouses which do not experience freezing temperatures. If you live in California, or southern France or Italy, you can grow these outdoors, but here in New England where winters are fierce, we must cultivate them under glass. If you have a plant window which is cold and very bright, you might want to try them indoors, but they are best grown with lots of light, sunshine and cool air temperatures. These are real greenhouse bulbs since they are primarily winter-growing species from South Africa.  They are relatively small in stature, they can make great temporary displays when brought indoors in January through March, when they are in bloom. Many of the species have amazingly complex patterning and unusual color combinations, perfect for the restless grower who is looking for something more interesting to grow in the winter.

I could easily have planted all of these species ( or ‘wild’ Gladiolus) in the same potting soil, since many South African species when cultivated under glass in small pots can be successfully grown in a fast-draining, lean soil mix which usually contains 1/3 sand, 1/3 pumice, and 1/3 commercial potting mix, but is is always prudent to research first. Many South African bulb plants prefer more clay, faster draining soil, and some might like wet ‘feet’ if they grow in seeps and seasonal streams. Many, like a few Gladiolus, prefer  to planted in the simplest of mixes, even pure sand, with only the slightest amount of organic material, or clay soils with no organic material ( I use a few handfuls of our local garden soil, un-sterilized, and granite chips in these cases).