|Pelargonium incrassatum, pink form|
|Oxalis cf obtusa|
|Massonia cf pygmaea|
At this point in January as we near the end of what started as a not too bad winter and are in a rather nasty cold and snowy phase that wont let up for at least another week, I, and no doubt many other gardeners, are really beginning to tire of winter. So aside from seed starting, there are some things to look forward to each winter season, and that is the flowering of the many winter growing South African geophytes in my cool garage. Under florescent lights and with the occasional help of some scarce winter sun, many species are grown in an environment that suits them well. The best thing would be a cool greenhouse, but short of that, my setup works pretty well. Adding some new t5 light setups has also made it even easier for some high light demanding items to be grown even better, though most of the plants are still under t12 setups. My indoor light gardens may be costly in terms of our electric bill but it allows me to stay sane in the darkest depths of winter.
The stars of early winter are the Cape oxalis spp, there are so many of them. Their nomenclature is a mess, since the last taxonomic treatment of this speciose genus (especially so in the Cape) was done a long time ago, well before DNA information became available for determining the true evolutionary relationships among the various species. But nature, of course, does not care how perplexed we can become in trying to make order of her handiwork so the proliferation of oxalis in the winter rainfall regions of South Africa is both maddening and fascinating. About the only thing they have in common are five petals, a complex fertilization system involving three tiers of stamens/pistils (sort of like the thrum and pin thing in primula, but worse), and bulbs. This latter feature is most unusual for dicots (or eudicots or wherever they are placed in the new classification system). It enables them to pass the dry summers totally dormant, and makes it easy to deal with in my garage too. When they finish growing and die back in mid to late spring, I just let the pots dry, clean off the dead foliage, and water again in September or October when temperatures drop and they show signs of stirring to life again. It is important to repot them every other year or so, because most make copious new bulbs, and the small pots I have them in get crowded quite fast. They generally grow fine in a mix of perlite and miracle grow container mix, but I am experimenting with pumice in place of perlite. The only way to get pumice at a reasonable cost in the east is to order Dry Stall (meant for horse barns but can be used as a soil amendment according to the website) from Agway. They have to order it in for you from their distributer and sometimes--like today--they get confused about the status of the company that makes dry stall--today they told me the company was going out of business, but a quick google search and phone call to the Dry Stall company proved otherwise, so I am on a mission to get it cleared up so I can get more pumice. This is not the same as Stall Dry, that is another product, you want the stuff that is made of "volcanic aggregate" as per the Dry Stall website. Its doesn't float like perlite, and is great for certain plants that don't like too much organic material in their mix, Worsleya being an excellent example. But most of the Cape oxalis are flexible when it comes to mixes, so long as they are kept cool (runs around 50F in my garage during the coldest parts of winter) and get good light. Most will survive and even bloom at higher temperatures, but not as well as at colder temps based on my experience growing them under lights in the old house at higher temps. Certain species such as O. obtusa in particular do so much better at lower temperatures. Some species can stand quite a bit of frost and I am testing some outside against the wall of the house, so far O. melanosticta has done the best, it flowers soon after it starts growing in fall so the flowers are not ruined by cold, then the leaves endure quite a bit of freezing. It survived last winter, which was quite a bad one. I am trying O. palmifrons outside too, this will be its first winter. It is not particularly renowned for its flowers, but it has most attractive foliage. It does survive outside at Plant Delights nursery in Raleigh NC. It also is one of the species I did not have success with at the old house, it really wants it bright and cool. Oxalis simplex (aka dregei) is an easy species that did well in both the old and new house. It grows in seasonally wet areas in habitat so no worries about overwatering this species. It proliferates quickly, even sending shoots out the drainage holes of its pot. Incidentally, unlike most bulbous plants, stems of oxalis can root and form bulblets, many form bulbets along the underground portion of their stem anyway. It is one of three unifoliate species I grow, the others being nortieri with thick leaves and the thinner textured O. monophylla. The foliar variation in Oxalis is as remarkably diverse as the surprising lack of diversity in the basic flower form, fortunately all Cape species have attractively colored flowers but many would be worth growing for foliage alone.
For variation within a species, look no further than O. obtusa, O. purpurea, and O. flava. All three species have a diverse array of flower colors and forms, and interesting crosses can be made among the different varieties, so long as they differ in placement of stamen and pistils--if they are arranged in the same way (there are three "levels", two for stamens and one for the five lobed pistil) then they will not cross. There are some oxalis I have that have species names that probably should be lumped with O. obtusa, it is a very polymorphic species with flowers in just about every color but blue or purple, and often has two toned blooms. It is easily the most diverse species of them all, and the different forms can hybridize to make a messy situation even more complex. The numerous small bulbs have characteristic raised ridges on them. O. purpurea in its typical form, with a pink/purple flower, is a common lawn weed in the Cape, but it also has numerous other color forms. O. flava in the broad sense always has succulent blue or grey green foliage with peculiar finger like blades that may be flattened or somewhat cylindrical in cross section. Unlike the other two diverse species, it tends to have bulbs that are fairly large, smooth skinned, and they dive deeply in pots and presumably in the ground as well. One could amass quite a collection of oxalis with just these three species, but there are many more, some of which trail, others make compact rosettes, and all are beautiful. O. fragrans lives up to its name, it smells like violets or pansies to me, a pleasant surprise since most oxalis don't have an appreciable fragrance. Telos Rare Bulbs is the best source of Cape oxalis in the USA, the owner Diana Chapman has made so many of them available at very reasonable prices, and she even ran a half price sale on them this past year. I brought in several species, mostly from South Africanbotanical gardens and some from wild collections (O. obtusa is everywhere in the western Cape) during my days as curator of the Desert Collections at NYBG. The real pioneer, however, in first bringing the Cape species into cultivation in the US would be the late Mike Vassar, I acquired many species from him, and over the years as people have learned of these wonderful and easily grown plants, species have traded hands back and forth. I reacquired some species I lost from Bill Baird, a podiatrist who is a self taught expert on the genus like no other person I have met. He grows only oxalis, and not just Cape oxalis species, and has a profound knowledge of them and has networked with just about anyone who grows or studies oxalis. He has also given me numerous other species both summer growing ones from the Americas and Cape species. He gave me my first bulbs of O. cathara, a rare species with beautiful thin fingered foliage and copious fragrant white flowers. In the US, most of the Cape oxalis would grow well in parts of California, but the various rodents there assure that most of them could not become invasive species, except the pervasive O. pes-capre, which must be the only species they don't eat, and it is a problem in parts of California. Gardeners in that state would do well to protect any oxalis they plant outdoors with wire cages around the bulbs to prevent rodent predation, much as we easterners need to do the same for crocus when squirrels and other rodents go after their corms.
Pelargonium is a much larger and more diverse genus than most folks realize, and most of them are either succulent stemmed or completely geophytic plants, dying down to tuberous roots during their dormant season. The species are harder to locate than most other plants but if one understands their natural cycle, they are not hard to grow. The winter growing dwarf species, mostly in section Horea, bear rosettes of leaves followed by flowers which range from interesting to very showy. Most of them can bloom the first year from fall sown seeds. The stunning Namaqualand Beauty, P. incrassatum is especially fast from seed. Its one fault is that the dense flower heads tend to run into the light tubes so I sometimes have to force them down by anchoring them under another plant to keep them from growing into the lights if I want to see the flowers and set seeds. It usually comes in screaming magenta, but I have gown pink and lavender forms sent to me many years ago by the late Charles Craib. Charles was another self taught expert on South African flora and producer of some fine books on the flora that are now out of print. He and Mike Vassar knew each other very well, and I had the pleasure of knowing both of them. Pelargonium nephrophyllum is a rare tiny species that flowers before the tiny leaves grow out, unlike most of the others that flower with the leaves or most often as the foliage is dying down. I am trying to increase my stock with some seeds from my own long lived plant. While many tuberous rooted pelargoniums produce extra "tubers" that are like small potatoes, I have not noted this yet with my plant of P. nephrophyllum so I set some seed this year by placing it under a new t5 setup to give it really bright light so it could make more than one or two seeds. I didn't end up with a lot, but I did get more than usual to try and increase my stock.
There is a whole world of small and not so small bulbs or corms to grow from the Cape. Lapeirousia oreogena is a stunning tiny species with brilliant purple flowers accented with wonderful dark markings. It, like all Cape bulbs, can be grown from seed sown in fall or winter when temperatures are cool. Many of these species need to first pass through a warm summer before their seeds will sprout so sometimes fresh seed from South Africa might not sprout right away. If already sown and nothing grows the first season, just dry the pot out for summer (as one would for the plants anyway) and resume watering in cooler fall weather, very often any recalcitrant seeds will then sprout. L. montana is an even tinier species with fragrant lavender blue stars, I will take photos of it soon and feature it in a later blog. Hesperantha is a genus that like Lapeirousia spans both winter and summer rainfall areas but is also more speciose in the winter rainfall areas of South Africa. The tiny H. hantamensis is far from the showiest species, but it grows on Hantam mountain which is about the coldest spot in the Cape, so when I have increased my stock I shall try some outside. It should easily be able to handle single digit drops (F) based on where it comes from. Only by experimenting with it will we know if it can also handle prolonged freezing temperatures, since while it experiences considerable cold at night in habitat, during the day the temperatures usually (but not always) rise above freezing. There are winter growing bulbs from the Mediterranean that survive fine here in New York, grape hyacinths and crocus come to mind so why wouldn't there be some South African winter growers that have that capability also? After all only 10,000 years ago the last ice age ended and while South Africa was not glaciated its mountaintops were certainly even colder than now so the ability to survive even colder conditions than experienced today surely lurks in the genetic makeup of some of the higher altitude winter growing Cape geophytes. I've had more than a few plants native to Florida or Georgia survive NY winters without complaint so plants often have long genetic memories and often more tolerance for conditions they do not experience in habitat today than we know.
Romulea is the (mainly) South African equivalent of crocus, in fact there is little botanical difference between them. The species depicted was grown from seed as an unidentified species, and without a more thorough knowledge of the different species I am not sure exactly which one it is. Many Romulea species show considerable variation in flower color which makes identification even more difficult. There are many different ones in both low altitude and high altitude regions of the Cape. Some of the high altitude species have stunning red flowers, looking more like species tulips than crocus.
Babiana hybrids are sometimes sold in the trade and will grow in California or perhaps the lower south if the summer rains aren't too much for them. Yet there is a plethora of wonderful species as well to choose from. Some stay small, such as the one shown which I collected seed of in the south Cape/Klein Karoo area, others grow a bit larger. Many have pleated leaves and the corms tend to dive deeply in their pots since they are preyed upon by various critters, including baboons. Some are wonderfully fragrant as well.
Freesia is not quite as speciose as the above genera, but it also has the same basic distribution with most species being winter growers. Many are fragrant to those who can smell them, apparently this ability is genetically controlled in humans. Freesia fucata is an early bloomer, most of the other freesia species I grow are yet to bloom.
Massonia is a small genus which has its own Facebook group (really, and when one grows them one can see why they would inspire such a group). The foliage is often the most fascinating thing about them, usually two leaves emerge from each bulb, very often they are flattened against the soil, and they may be smooth, hairy, green, or variously marked. The paintbrush like flowers emerge from the middle and may be fragrant or may not smell so good. Usually white, they can be pink or even reddish and close relatives in the genus Daubneya can be quite brilliantly colored. The black round seeds are easy to harvest but so smooth they often escape when trying to separate them from the chaff on a piece of paper.
Lachnalias also have smooth round seeds but there are many more species than in Massonia. Only one species is said to be summer growing, the elusive L. pearsonii (not to be confused with a hybrid of the same name) from Namibia, but there are a few winter growers that maintain the winter growing habit even when they live in summer rainfall regions. Lachanalia viridiflora is a stunning blue green flower, and is also very rare in habitat, being restricted to the Vredenburg area. Luckily it grows well in cultivation. It is self fertile so from one bulb I brought from Rust En Vrede nursery back in the early 80s numerous offsets and seeds were produced over the years such that NYBG has many from what I brought into their collections, and I have grown some from the abundant refrigerated stash of seed I have of this species. It is among the first lachenalias to bloom, and will often flower its second year from seed. Its hard to believe it is critically endangered in habitat, as it is so easy to grow and propagate. I recently acquired a copy of The Genus Lachenalia by Graham Duncan of Kirstenbosch fame. It was expensive but well worth its cost. One can see how much effort Graham put into this meticulously researched and well illustrated book. His personal experiences with the various species are informative in a way that too few horticultural/botanical books have, which makes this book even more appealing. I like when its obvious that an author has a passion and profound knowledge about their subject.
I've blogged about Walleria gracilis before, and by now I know more of its weird ways. It is another species that is quite restricted in where it lives, and is one of a handful of species and in this case the only winter growing one. I have found that it is self fertile, and also have seen it growing well at Wave Hill in the Bronx. They also have many seedlings coming along. Its not hard to grow but it is a vine. It forms a fairly large tuber and my plant did not awaken last year so eventually I dried it off and this fall it came up like nothing happened. So if you grow this species at some point don't be alarmed if it takes a year off, it isn't dead its just sleeping. It blooms for quite a while and the flowers resemble Solanaceae flowers and also probably are "buzz" pollinated by bees in their natural habitat.
Besides Telos for bulbs, many more species of Cape flora can be obtained from Silverhill Seeds in South Africa (they ship all over the world), and some are also carried by Lifestyle Seeds. There are also a couple of other reputable seed suppliers in South Africa, and some of the bulb and cormous species show up in seed exchanges such as NARGS and SRGC.
With the coming of spring more pelargoniums, oxalis, and "bulbs" will come into bloom while others set seed with my help in ensuring their pollination. They provide a source of continual pleasure right through the season most gardeners in temperate climates dread, well until after the outdoor gardens have begun to spring into action.
Oxalis melanosticta in fall 2013
Oxalis melanosticta in December 2014