Arilbred Irises: A Touch of the Exotic

by Tom Waters

One of my favorite types of iris is hardly known to the general gardening public: arilbreds. These striking plants are deserving of much more attention.

What is an arilbred? The term aril applies to two groups of irises: the oncocyclus from the Middle East, and the Regelias from central Asia. (The word "aril" is a term for the prominent white color seen on the seeds of these types of iris.) These aril irises, although some of the most spectacular flowers in the genus Iris, often proved difficult to propagate and maintain in northern Europe or the US. Arilbred irises are the result of crossing these aril irises with the more familiar bearded irises. Many earlier breeders making these kinds of crosses were dreaming of flowers like those of the aril irises on plants that were as easy to grow as bearded irises. Today, this dream has largely become reality. Along the way, the endless gene combinations gave rise to a huge variety of flower types not even imagined before.

Seeds of an oncocyclus iris. Note the fleshy white collar or "aril", from which aril irises take their name.

Arilbred irises come in so many different colors, patterns, and forms that it is unwise to generalize about their appearance. Many, however, have large, globular blooms, a dark signal spot below the beard, and intricate veining.

'New Vision' (Tasco, 2012). Note the large dark signal and globular form. (Photo: Superstition Iris Gardens)

'Navajo Velvet' (McAllister, 2009).

'Oyez' (White, 1938). Note the intricate veining.

Arilbred irises grow extremely well in the western US and similar climates. They prefer conditions that are on the dry side during the heat of summer and the cold of winter, although they are not desert plants and will thrive on ample irrigation during the spring and autumn. In the desert southwest of the US, arilbreds often perform better than tall bearded irises, growing more rapidly and blooming more reliably. Growers in wetter climates, such as the eastern US, often find them more challenging to grow, although many are successful with them nonetheless. If you live in a wetter area, I recommend giving your arilbreds a particularly sunny spot with good air circulation and good drainage.

'Parable' (Johnson, 2011). (Photo: Mid-America Garden)

'Eyes on You' (Black, 2012). (Photo: Mid-America Garden)

'Refiner's Fire' (McGrath, 2007). (Photo: Pete McGrath)

'Aladdin's Gem' (Thoolen, 2002). One of the smallest arilbreds.

Arilbreds come in all sizes, from tall-bearded size to dwarfs only a few inches high. This is because all different types of bearded irises (tall, median, and dwarf) have been used to breed them, and also because the aril species themselves come in a wide range of sizes. Most arilbreds bloom earlier than the TBs, overlapping the standard dwarf bearded (SDB) and intermediate bearded (IB) bloom seasons. They do not have the branching and bud count seen on TBs: a single short branch and 3 to 4 buds is typical of many arilbreds. They make up for it with individual flowers that are showy and spectacular, and by often producing many stalks, even on a young clump.

Have you tried arilbred irises in your garden? How do they like your climate?