Saturday, August 21, 2010

Not Your Average Bearded Lady

Bearded irises are sorted by size into several categories. Miniature dwarf reach a height of 8” or less and their blooms are around 1-2” in diameter. Standard dwarf get 8-15”, intermediate reach 16-27”; miniature tall (excuse me?) grow to 16-25” and produce small flowers; border iris are 16-27”. The grandes dames are tall iris (is that tall? Or tall tall? Big tall?) that can reach 38”. Bearded iris tends to bloom by size in order from smallest to largest.

So, as a miniature dwarf, Iris pumila is one of the earliest blooming of the rhizomatous irises. Though not nearly so early as the tiny reticulated irises, I. pumila shows promising buds before the end of March and can be in full flower in April.

Iris pumila is a natural hybrid between Iris pseudopumila and Iris attica that is native to central Europe. Its native habitat is dry grassy lands; like other bearded iris it loves to bake in the sun and hates wet feet.  A raised bed or rock garden will insure perfect drainage. Place this tiny titan at the front and give it room. Division is usually required in the third or fourth year; you will want to do it as soon as the blooms have faded. If you must fertilize be sure to use low nitrogen and be stingy.

Iris pallida, sometimes called sweet iris, orris or Dalmatian iris, is native to the Dalmatian coast of Croatia.  This rhizomatous bearded iris produces fragrant, pale lavender-blue flowers with yellow beards. In late spring to early summer, blooms appear atop stems which may get to 40” tall. I always thought that ‘Variegata’ had cream and green variegation and ‘Aureovariegata’ was green with yellow stripes. According to the Missouri Botanical Garden, these two varieties are synonymous and feature gray-green leaves variegated with stripes of creamy yellow. Despite its association with the tricky bearded iris clan, it has been selected as a GPP for the Pacific NW.

To make things more confusing, Iris pallida ‘Argentea Variegata’ (aka ‘Albo viris pallidaariegata’) does have pure white variegation attributed to its leaves. However, the GPP organization characterizes this variety as less vigorous than ‘Variegata’. Whatever variety you choose, this is one iris whose foliage is more beautiful than its bloom-and since the bloom is both pretty and fragrant, it is a no-lose proposition.

Iris unguicularis (née Iris stylosa) is the winter blooming Algerian iris. It often starts in October and produces blooms through March or even April and is considered hardy in zones 7 to 9. When the temperature dips below about 10 degrees, however, any flowers and buds will freeze and be lost. Happily, if the weather warms up, the plant will re-bud and be in full bloom again within a week.

Iris unguicularis has tough, sometimes ribbed, leaves ½” or less in width and anywhere from 1-2 feet long.  The plant can be unprepossessing, but the flowers are dramatic-especially in the dead of winter. Blooms tend toward shades of lavender but can be pure white to deep purple to slightly reddish. The flowers are sweetly scented and can be cut and brought inside.

This iris is native to the dry Mediterranean climate. It is a bit tender and if the temperature drops to 0° F. the foliage will die to the ground. Usually it will recover and in the spring grow new foliage. I. unguicularis can survive the winter cold and even the steady rain of the PNW, but it requires excellent drainage and a good baking in the hot summer sun. If you plant it against your foundation on the south side it will enjoy the heat, stay dry in the summer and the lime leaching from the concrete will contribute to the neutral to slightly alkaline soil it prefers. At the least try to find a south facing section of your garden in the full sun.

It resents drying out completely; you may need to water once or twice during the summer if there is no rain. The flowers are held low in the evergreen foliage and you might want to cut it back to about 10” in late August so that you can enjoy the flowers. Like most irises, a low nitrogen fertilizer can be applied before and then after flowering. The biggest problem you face with this unique iris is slugs. Imagine their delight upon finding this treat in midwinter. You must be diligent about baiting for slugs or you may never see any flowers.

Iris unguicularis may be propagated by dividing the rhizomes, but I have found in my garden this plant is slow to colonize. You can also allow the seed pods to dry on the plant and collect the seeds or allow the plant to self-seed and then move the seedlings. It may take two or three years for the plant to produce flowers.

What an amazing genus. You can have some kind of iris blooming almost any month of the year if you are willing to hunt for them!

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