Schwantesia herrei (2004)

By Mike Hellmann (April 2004)

This specimen plant attendance prize was previously cared for by Ann Grace, a club member who recently passed away. After she purchased it as a 4-year-old seedling in 2007, it soon became her “pride and joy.” She did well growing this challenging plant. This is the first non-woody mesemb I’ve owned – ever. Now it’s really growing on me.

Schwantesia falls into a group of succulents known as mesembs. The family was once known as Mesembryanthemaceae. but has been since renamed Aizoaceae. I’ve always been intrigued by memembs. Yet, other than the trichodiadema and mestoklema shrubs with their twisted bonsai-ish forms, I’ve never owned anything else that falls into this huge mesemb group.

I’m the “tree, cactus and euphorbia guy.” I’ve always been selective in my plant choices due to the fact that there are way too many plants out there to collect them all. Or could I be a stick in the mud, being possibly a bit skittish of taking on plants that are reputed to not do well here in the St. Louis area?

About eight years ago, we asked Dan Mahr to be a judge at our summer show. After the event, he commented that our show represented all succulent families well with one exception. Yes, mesembs. He was right, and this seems to still be the case.

High humidity and hot summers are our first excuses, and they do carry some merit. Yet last year, John Trager gave us a list of lithops (also in the mesemb group) that would do well in our climate. I do believe we can have a better representation of this plant family in our collections.

There are many advantages to growing them. They’re small. They’re inexpensive. They’re very interesting to grow and can be absolutely beautiful.

As stated above, Schwantesia is in the family Aizoaceae, which includes all the plants we know as “mesembs.” This genus was named after Gustav Schwantes (1881-1960), who was a German professor of pre-history at Kiel University and a mesemb specialist.

The home of schwantesias is in the lowest-rainfall regions of South Africa, including deserts in the Richtersveld and Namaqualand of Northern Cape, as well as the southwestern corner of Namibia. Schwantesia herrei v. herrei is a winter grower that has golden-yellow flowers, which open only at sunset in the autumn just prior to the rainy season.

Most schwantesias are reported to be quite easy to grow – assuming one follows the rules. They are winter growers, so their primary growing season is winter, after which they transition into dormancy for the hot summer months. Originating in such harsh, dry areas, this plant requires less water than most succulents. If given too much water, its leaves can split open, resulting in permanent, unsightly scars.

Schwantesias are similar to lithops and other mesembs in that their bodies are made to store water. A regular watering regime from autumn through spring should be followed. Allow to dry and water minimally in summer, only when the plants start to shrivel.

Steven Hammer, a mesemb expert and owner of the Sphaeroid Institute, has always advised never to let dormant plants go completely dry, as this destroys root hairs and prevents the plants from resuming normal growth. He says that most mesembs can be treated like lithops. Mesembs have an annual cycle that differs little year to year. He calls them “genetically fixed.”

These plants, as you might assume, require good drainage with a generous portion of aggregate in the soil mix. One is advised to keep this plant cool and shaded in summer with an occasional splash of water, as we often offer other winter growers. It needs full sun or light shade when actively growing for best growth. Surprisingly, schwantesias are relatively hardy to temps down to -2 degrees C.

I want to thank both Steven Hammer and the Cactus Art Nursery for some of the information in this article.