Grow Dwarf Bearded Iris for Drought Tolerant Beauty

by Jane Shellenberger:

A stroll through the blooming fields at Long’s Gardens is a traditional Mother’s Day treat for anyone in the vicinity of Boulder, Colorado. Still family-owned, this iris farm on the north side of town grows bearded varieties only, because they grow so well in Western climates and tolerate many different types of soils, including our more alkaline ones. Long’s had its 100th birthday a few years back. Catherine Long Gates, granddaughter of JD Long, who came to Colorado in search of a drier climate and started the business, runs the now urban iris farm with her husband, Dennis Gates.

I stopped by Long’s recently to see if any Arilbred irises were in flower. Their ancestry includes Aril irises from dry regions of the Middle East, which makes them extremely drought-tolerant. Arilbreds are a favorite of Lauren Springer Ogden, which is where I heard about them. While I didn’t see any Arilbreds on that particular day, some of the miniature and dwarf irises were still in bloom, positively glowing in the soft, overcast light. Whenever the sun broke through they became illumimated like little multicolored jewels.

Catherine and Dennis told me that in April, when the smaller irises are blooming, visitors sometimes look around and ask for “the real irises,” by which they mean the tall ones. Fortunately, some gardeners prefer uncommon beauty. Besides being exquisite, the miniature and dwarf irises have the advantage of being small in a sometimes very windy place, so they don’t blow over or snap off like the taller varieties. They also form nice, manageable clumps that only need to be divided every five years (vs. every three years for the tall irises), and stagger their blooms so several are in flower at once in each clump. An individual iris blossom usually lasts three days if it isn’t hot, dry, and windy. The smaller types flower earlier – miniatures in late March to mid or late April, standard dwarfs from mid to late April through mid May – when the weather is usually more conducive to blooms that last. In fact, it’s possible to create a continually unfolding season of iris in your garden from mid March to early June if you plant all the different types.

Bearded irises grow very well without a lot of moisture, which is why JD Long planted them in Boulder in the first place. Another big plus is that the leaves are toxic to deer, and though they may eat some young leaves early in the season, they usually leave them alone after that, which means that unlike tulips, you can actually grow bearded irises in the mountains along with daffodils. Though deer often browse the fields at Long’s, Catherine says that contrary to what people think, they’re eating weeds, not irises. Because they’re small and low, dwarf and miniature irises should be planted as a focal point, in a place where they’ll be seen - on a berm or slope, in a rock garden, near a front door. Many are bred to be viewed from the top. And while the taller bearded irises have been hybridized extensively for color and form, to the point where most have lost their scent, many of the smaller ones are still fragrant.

All bearded iris are easy to grow in any soil that’s well drained with at least a half day of sun. Give clay soil some amendment to lighten it up. They don’t do well in low, wet spots and usually not too well in pots either. Irises like to keep their crowns dry, especially during the winter so don’t use organic mulches; pea gravel is a better choice.