Well actually both species pictured here can be thugs, but when they bloomed together they made a pretty sight. Campanula poscharskyana makes a pretty spreading mat, while Corydalis ochroleuca forms clumps wherever it can get a foothold. The corydalis is more aggressive and taller than the campanula in my garden, so I do remove excess corydalis plants after their first flush of blooms. The campanula flowers in spring, but the corydalis can keep flowering off and on throughout the growing season, especially in cooler weather, and is one of the last things to succumb to heavy frosts in the autumn.
Friday, February 25, 2011
The genus Oxalis is probably best known for its few weedy members, but in fact the vast majority of them, and there are hundreds of different ones, are beautiful plants. Most of them grow from bulbs, an unusual feature for a non monocot plant. This one is probably O. nelsonii, a summer grower from Mexico. I got it from Bill Baird, who is the man to go to for anything oxalis in the USA, he only grows members of this genus, and has developed an elaborate setup to be able to grow them well in Brooklyn. O. nelsonii is a summer grower, making it simple to grow for those of us with a yard. Simply water in spring, watch it woosh into bloom and growth, keep watering and occasionally supplying fertilizer, and dry it off in the fall and bring indoors. Store dry until the cycle begins anew. It is before the first watering that one can remove excess bulbs from the pot and start other pots, for many of even the desirable oxalis species are able to multiply well when conditions are to their liking. No need to worry about this one taking over, though, as oxalis bulbs are eaten by rodents, though that is not generally a problem in my home garden. Gravel on top of the pot does discourage the more significant problem of squirrels, which like to dig in my outdoor pots.
Many more bulbous oxalis are found in South Africa, and all but a handful of these are winter growers. They do best in cool greenhouses, but I can grow them under lights, so long as they are kept dry for summer. They do bloom, but not with the abundance they do in cool greenhouses or outdoors in favored locations like California. Telos nursery is an excellent source for many such species.
Bletilla striata is both beautiful and easy to acquire. It has persisted for years in my home garden, though it expands during mild winter years and shrinks back during hard winters. It is cheap to buy making it easy to get replacements if they were ever needed. It has never self sown in my garden, but does set seed. I have grown, with limited success, some of those seeds sown on sterilized potting soil, but the seedlings are tiny and slow. In fact, its amazing they actually grew at all, since most orchid seeds will not germinate without special in vitro techniques as they require a fungal partner for success in nature. Recently I sowed seed on orchid media agar at school, using a microwave to prepare and sterilize the medium, and hydrogen peroxide as a sterilant. I did so in a laminar flow hood I got on ebay for 75 dollars (it was quite a project to get it hauled from New Jersey to the school, and then moved into my classroom), but I did not turn it on, as I suspect the hepa filter needs replacing. A couple of months later I have baby food jars full of nice young plants which will probably be ready for tranfer to soil well before school is out. With a little luck, I should be able to substantially increase this patch of bletilla, and add others, including some in my school gardens. After all, one can never have too many orchids in the garden!
This species came in a seedmix sent as a free gift from a nursery on the west coast, and I was unable to figure out what it is for the two or three years I have had it. Finally I posted some what is it pics on the facebook group "Plantporn" (a plant geek group, obviously!) and got an identification. Apparently it mainly occurs in the southwest, but can be found in other states, even New York, though I have never seen it before. It behaves as a resowing annual here, growing about 3 feet tall and blooming from mid/late summer to frost. Copious seeds are produced, but it doesn't seem to produce excessive numbers of offspring thus far in my school garden, rather just enough to regenerate a few plants. I also save seed, which would be useful if I wanted a bigger display of it, though space is always at a premium given my penchant for high diversity in my gardens. Nothing seems to bother it, but pollinating insects are fond of it, and it is pretty much a carefree native species worth inclusion in a sunny garden.
This cold hardy gazania was grown from seed, though the same thing is often marketed as "Colorado Gold" in better nurseries. It grows in the high Drakensberg mountains of South Africa, and is reliably perennial by all accounts in places like Denver, though winter wetness may be a more significant problem for its survival as a perennial here in NY. I will soon find out if they made it through our winter as the snowpack melts (and if the voles that apparently were eating things in parts of the school garden, protected from predators by the consistent snow cover, missed them). In any case, they are easy to grow from seeds as annuals too, but it takes more than one plant to set seed, as all gazanias in my experience are self infertile. I've also made some interesting hybrids with this species and other gazania species and cultivars, and hope to flower many more of them this year as well as to test them for cold hardiness. Gazanias do require good sun, and the flowers won't open without full sunshine. Unfortunately, they are edible and can be attacked by rabbits and presumably other herbivores, but deterrents of the same order as used to repel deer, as well as interplanting with less tasty/toxic neighbors, do repel herbivores.
Well, actually I suspect that this is a species of Ageratum, but whatever it really is, it is a nice Brazilian plant that looks good in the garden and also doesn't mind being lifted before frost and brought indoors. In fact it continues to bloom and set seed in my classroom under lights at this moment. I hope it turns out to be daylength neutral, as I suspect, since it continues to set new buds indoors, though it did not begin to flower until fall outdoors, however the 2 plants were small when planted out rather late, and may simply have needed to get big enough to bloom. If it is daylength neutral, it will make a far more valuable contribution to the garden in northern climates than if it requires long nights to flower, since it could be grown as a summer annual. I rather like the foliage better than the messy leaves of the common garden ageratums, this specie's leaves are not so bristly and have a more substantial texture. It also appears to set numerous seeds by itself, but I have not tested these for viability yet. Most Asteraceae are self infertile, but some set copious seed via self fertilization or even apomixis (a kind of cloning via weirdly produced seeds, common in Taraxacum officinale, for example). I'm looking forward to propping it soon and setting more plants out next year in the garden, it is a pretty thing, and as might be imagined, butterflies and bees do love it.