On Gardening: Golden thryallis a must for the long, hot summer ahead

June 29, 2015

The golden thryallis and the royal purple of the princess flower makes for a dazzling summerlong combination.

You would think a shrub or summer annual that blooms all summer and is drought-tolerant and deer-resistant would be award-winning across the country. At least golden thryallis is a Texas Superstar winner and one you will want to grow too.

It certainly needs to go far beyond Texas to any area of the country that gets stifling hot over the long, hot summer months. When you want to wild and go indoors, this workhorse of a plant just gets better.

There is a good chance you donít know golden thryallis, which is also commonly called showers of gold. Botanically speaking, it is Galphimia glauca and is native from Mexico to Central America and Paraguay.

It is in the Malpighiaceae family, which is also fairly unknown to the majority of American gardeners. Plants like the Barbados cherry (Malphigia glabra, native to Texas) and the butterfly vine (Mascagnia macroptera) are two other relatives starting to creep their way north into the green industry trade.

The golden thryallis has a long list of attributes that makes it a winner in the landscape. First and foremost it has unstoppable blooms from late spring or early summer until it freezes. This means it is exceptional value for your gardening dollar.

It is considered a Zone 9 and warmer plant, though it has come roaring back for me in Zone 8 after temperatures in the high teens and low 20s. Even if yours doesnít and you grow it as an annual, then you can at least celebrate that you had terrific golden yellow flowers blooming for more than 150 days.

Every single week someone asks me what flowers they can grow that are resistant to deer. I am happy to say golden thryallis is resistant; it is not on the menu of the Big Buck Cafť.

The golden thryallis will reach 4 feet tall and a little over 4 feet wide, undoubtedly larger in Zones 9 and warmer. The flowers are borne on large spikes in what almost resembles clusters of blooms. The flowers partnered with the blue-green foliage and red-tinged stems make this a truly outstanding shrub.

Once you locate yours, plant it in fertile, well-drained soil in full sun. A little shade or filtered light is tolerated, but wet feet spell doom. Great drainage increases the chances you have of a spring return. It is drought-tolerant once established, but keep in mind supplemental water during prolonged dry periods will make sure those glorious yellow blossoms just keep coming. The golden thryallis also makes an exceptional container plant, allowing you to simply tuck it indoors by a sunny window.

Over the years Iíve seen some dazzling combinations. The most unique was with the princess flower, Tibouchina urvilleana. The pairing of royal violet and the golden yellow was truly stunning. At the Coastal Georgia Botanical Gardens we have some partnered with the blazing red fire spike, Odontonema cuspidatum, and others with Mystic Spires blue salvia.

My favorite partnership, however, may be where we have it growing with the dark purple foliage of the Princess Caroline fountain grass developed by Dr. Wayne Hannah of the University of Georgia.

One thing I can guarantee is once you start growing golden thryallis, you will never want to be without one to enjoy for the long, hot summer.



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