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Diascia (Twinspur)

© Jojo Sigurgeirson

This member of the scrophulariaceae family is much like it's relatives. It's got tubular flowers on a spike much like the familiar foxglove. It's got lips and a throat to each flower sort of like a penstemon. It's got spurs like a Nemesia.

It's also similar because it's fairly easy to grow, although this one is quite tender in cold areas. In most texts I've found on Diascias, the hardiest of them all (Diascia integerrima) can take zone 7b. If you are gardening in colder zones, I would experiment with this, Diascia fetcaniensis and Diascia vigilis.

In this article I think you will find the links at the bottom of the page will give you the most information about Diascias. The information I have provided will give you just a glimpse of what Diascias are about. So by all means, visit the links if this breif primer sparks your interest.

Tall Diascias
This is Diascia rigescens, the taller of the bunch. It grows on very stout stems and produces a slender spike in early-summer. This was then pinched back and well fed with compost, resulting in a bushy habit with many flower spikes to 3 feet tall.

Diascia rigescens is hardy to about -10 degrees celsius.

For a close-up of Diascia rigescens, see this discussion, where Gay Klok of the Tasmanian Garden Journal guessed it's identity.

Short Diascias
Most of the Diascias available in nurseries today are the short-growing types. These include varieties with names such as "Ruby Feilds", "Appleblossom" and "Hopley's Apricot". The flowers of the hybrids are small and densely packed onto short spikes to 18 inches tall, some growing taller with age, although they flower best if kept small by pinching and deadheading.

These make very nice additions to small flower borders and containers. In a large flower bed they can become lost but well taken care of will grow to form a mat spreading to 2 feet wide or more with age.

How to Care for Diascias
Diascias like lots of sun, but in hot-summer areas some shade will help keep them blooming. They are said to like a cool root zone, so much like a clematis, their roots should be shaded from hot blazing sun. Diascia 'Ruby Feilds' is a popular type but doesn't withstand hot situations and tends to melt in the average American summer.

They are not that particular about soil but prefer rich soil on the alkaline side and good drainage, especially in the wintertime. NO STANDING PUDDLES TOLERATED. The short types are often grown in rockeries, where their casual habit of growing can be useful between rocks.

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