If you’ve been out shopping recently, you already know this, but for those of you who prefer to stay indoors, I’m happy to announce that “bulb season” is now underway. Garden centers, big box stores, and even supermarkets are overflowing with pretty, colorful packages containing bulbs to plant in the fall. If your only experience with this phenomenon is limited to the meager displays in supermarkets and big box stores, however, go check out what’s happening in garden centers: the selection is incredible!
But why now, you ask? Because bulbs planted in the fall will produce the first flowers of next spring. Without bulbs, our flower beds will be empty or nearly empty for the first two months of spring. However, with a good selection of bulbs, including very early, early, mid-season, and late varieties, we can ensure a continuous display of color from April to June.
Small Irises
It’s impossible to show you all the flower bulbs that are currently on sale. Instead, let’s take a look at a unique category: small bulb irises.
Gardeners are more familiar with large garden irises. With their tall stems and multicolored flowers (“iris” means rainbow), they beautify our gardens in early summer, but long before that, there was another kind of iris, small miniature irises, barely 15 cm (6 inches) tall. Unlike large irises, which grow from fibrous roots or rhizomes, small spring irises are bulbous plants. Their small bulbs resemble miniature onions. They are planted in the fall, between September and the arrival of winter, and they bloom early in the spring, very early. I can’t give you an exact date, as it all depends on the winter we have, but normally these small irises bloom less than a week after the snow melts. In fact, when they bloom, there is often still snow around!
Lots of Choice
There are dozens of varieties of bulbous irises, but the selection in stores is not always very comprehensive. However, garden centers should have at least one or two varieties. The selection is much wider when ordering by mail.
There are two groups of small bulbous irises: “blue” and “yellow.”
The blue group mainly includes two species that are very similar: the reticulated iris (Iris reticulata), which is the most common, and the winter iris (I. histrioides), as well as hybrids between the two. Their main characteristic is that they produce surprisingly large flowers for such a small plant. To give you an idea, the plant is no more than 15 cm tall when in bloom, while the flowers are 6-8 cm in diameter! They are sold in shades of blue and purple, with a few varieties with white flowers. In addition to their base color, the flowers are always marked with yellow and white. Cultivars include ‘Harmony’ (royal blue), ‘J.S. Dijt’ (dark purple-red), and ‘Cantab’ (centaury blue). Blue irises are easy to grow and return faithfully year after year. Over time, the number of bulbs increases, as does the number of flowers.
There is only one commonly available species of yellow iris, Danford’s iris (I. danfordiae). The flower is slightly smaller. Also, the leaves appear after flowering (in blue irises, the leaves appear during flowering). This plant flowers well in its first year, but tends to disappear after that: it should be considered an annual bulb.
Finally, there is a small category of bulbs: hybrids between yellow and blue irises. These produce a unique coloration, blue-green with yellow and black markings. From this select group, only I. ‘Katharine Hodgkin’ is readily available. However, it is probably the best of all bulbous irises. Its flowering increases rapidly over the years: a planting of 10 bulbs can produce a mass of more than 100 flowers in 3 or 4 years!
Don’t Confuse Irises!
Caution! There is another bulbous iris sold in the spring: the Holland iris (I. x hollandica). It should be avoided, as this zone 6 or 7 bulb does not grow well in Northern regions. Sometimes it survives the winter, but dies shortly thereafter, usually without flowering. I am always surprised to see local stores selling them: this is not a service to their customers. Unless, of course, they are sold exclusively for forcing indoors.
How can you tell the difference between “good irises” and “bad” ones? First, by their names: reticulated irises, winter irises, and Danford irises are the good ones; Dutch irises are the bad ones. But you don’t even have to remember the names if you remember that hardy irises are small (about 15 cm/6 inches tall) while non-hardy irises are large (50 cm/20 inches and taller). This is always indicated on the label.
Planting and Caring for Bulbous Irises
Nothing could be easier than planting iris bulbs. In a well-drained spot that gets sun in the spring (small irises will be dormant in the summer and are not bothered by summer shade), dig a hole 4 to 5 inches deep. Place the bulbs in the hole about 12 to 15 cm (5-6 inches) apart, with the pointed end facing up, cover the hole and water. There is no need to worry about animals such as squirrels digging them up: they don’t like iris bulbs!
There is nothing special to do during flowering. After flowering, you will be surprised to see the narrow, short or absent leaves during flowering grow to a height of 25 to 30 cm (10-12 inches). They disappear after a few weeks as the bulb enters dormancy for the summer. If you need to move or divide the iris bulbs, this is the right time to do so.
Spectacular flowers for so little effort and so little money? Plant some small bulb irises.
Larry Hodgson has published thousands of articles and 65 books during his career, in both French and English. His son, Mathieu, has made it his mission to make his father’s writings accessible to the public. This text was originally published in Le Soleil on September 30, 2006.
Here in Virginia the Dwarf Crested Iris (Iris cristata) is a tiny native Iris. Soooo cute! Very hardy for us. Spreads steadily in a dry, west-facing, wooded area with no care. Blooms April – May. The foliage remains as a short ground cover.
I planted some blue ones years ago. They come back every year and are still spreading. Funny thing is the very blue flowers have switched to a darker purple!