Hi all Most of the winter growing south african species of Oxalis should be quite winter hardy. Some beautiful species and forms are found in the vicinity of Sutherland, which is regarded as the coldest place in South Africa, with daytime (winter) temperatures often below 5 degrees Celsius, and night temperatures well below zero(up to -15 !). (Over the whole year an average low of 3 degrees, and an average high of 20.5, according to http://www.sutherlandinfo.co.za/). It must be remembered that very few Oxalis in cultivation will produce seeds, as it is not self fertile. However, when large quantities of various clones or collections of the same or similar species are cultivated, seeds might be produced. This could happen with Oxalis obtusa, the Oxalis flava/fabaefolia group, O. purpurea, O. luteola, etc., of which many different forms have been collected and are available. So if only one clone is grown no seeds will be produced - this is true even for Oxalis pes-caprae! (this, however, is not true of the weedy Oxalis of the America's - but then they are mostly annuals, and do not produce bulbs). All the "spreading" and "invasiveness" of (South african) bulbous Oxalis is thus more due vegetative reproduction, and if Oxalis are kept in a pot, this should keep the species where you want it to be. I say should, becouse Oxalis roots can grow very deep, and if the pot is placed directly on (or in) a suitable growing medium, the roots can go through the holes in the pot and into the soil, and voila ! an escapee ! - most probably this is the source of Jane's plants in the plunge sand. Most Oxalis renew their bulbs each year, and various different forms of vegetative structures (stolons, rhizomes, runners, etc.) are formed, along which bulbs can develop. Species with these structures are more invasive than those who just quietly multiply where they are. Oxalis lawsonii (which is a spectacular species) is reported to produce bulbs up to a metre from the orriginal bulb in a single season. Many forms (not all!) of O purpurea (and similar sp.) do not form these structures, and will multiply locally, but do not spread as much or as quickly. Unfortunately the underground system of Oxalis is not well studied, and the info that's available are not easily accessable. The easiest method to test an Oxalis' ability to spread is to plant a single bulb in a large pot, and check it the second year to see where all the new plants pop up in the pot. If it is in the centre (where the orriginal bulb was planted) it is not aggresive, if plants pop up all over the place underground runners or stolons have been produced, and the species are thus more aggresive. And luckily most unwanted Oxalis succumb to a single touch of a brush dipped in a systemic herbacide . . . Christiaan ----- Original Message ----- From: "Lauw de Jager" <email@example.com> To: "Pacific Bulb Society" <firstname.lastname@example.org> Sent: Tuesday, April 28, 2009 10:24 PM Subject: Re: [pbs] Acceptable Oxalis Dear all, It is very hard to overcome the prejudice against Oxalis. I offer about 15 species and forms and try to be very careful not to offer species which can spread dangerously.