Cultivation of Oncocyclus

Much has been written on the Cultivation of Oncocyclus. For various opinions check out; The oncocyclus irises are perhaps the most challenging species to cultivate in gardens outside their native range. The principal difficulty is that they require a hot and very dry summer dormancy period for about 3 months after blooming. Wetness during this period can swiftly lead to rot. Winter hardiness is a secondary issue, and only for some of the more southern species from Israel.

Many different methods have been developed for caring for oncocyclus iris during their summer dormancy. In cool, wet climates (e. g., England), most growers make use of a bulb frame or greenhouse. The bulb frame is an elevated bed that is fitted with a glass or plastic cover to keep rain from reaching the bed. The cover is put on after bloom and left in place until growth resumes in the fall.

Another method is growing in pots, which allows the plants to be moved to a dry location during summer. Although this is effective, a number of growers have commented that the irises do not perform so well when their root growth is restricted in this way.

The rhizomes may also be lifted when they go dormant and stored in a dry place for replanting in the autumn. Again, although survival is good with this method, it makes it impossible to have a strong, established clump that performs to full potential.

In areas where summer precipitation is scant, oncocyclus can be successfully grown without protection, provided there is excellent drainage. A raised bed can be used where the natural soil is heavy.

The related regelia irises enjoy the same culture as oncocyclus, but are somewhat more adaptable to departures from the ideal.

Recommended soil additives are lime (if soil is added), gypsum, sand, or gravel. Many growers use a gravel mulch. In areas with cold, wet winters, a sand mulch over winter can be helpful.

Although water should be withheld during summer dormancy, there is no need to be stingy with water during the spring growth period. During the spring months, the oncocyclus must "make up for lost time" and require ample water and nutrients.

Opinion is divided about whether autumn growth should be encouraged. It depends both on the habitat of the species involved and the climate of the garden where they are being grown. If winters are mild, some autumn growth will be beneficial for most. Gardeners with severe winters may want to water sparingly in the fall, to help harden the plants off for winter.

All these comments are generalizations. The experience of different growers varies widely. Learning to grow oncocyclus irises well requires a willingness to experiment and accept some losses along the way. For gtowers who do not want a challenge I would reccommend the easy Arilbreds.

See also ; Cultivation of Oncocyclus by Lynch 1904

 

-- Main.RPries - 2010-02-01
Topic revision: r5 - 31 Oct 2013, BobPries
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