pbs Digest, Vol 18, Issue 29

oooOIOooo via pbs pbs@lists.pacificbulbsociety.net
Sat, 25 Aug 2018 12:11:58 PDT
Tom John wrote

> I am a newly converted South African geophyte enthusiast with a large order of Oxalis & other Winter growers ready to pot up. I had envisioned potting some of the smaller varieties in 3" [7.5cm] deep bonsai type pots.... ...recommendations otherwise as to optimal depth and space
preferences for oxalis, the iris groups and others.

Before potting up you need to read how large your plants become, and do some thinking. Some bulbs are small enough to grow and flower well in shallow containers, but most are not. Some people are limited by needing to grow inside a house or glasshouse. I have the luxury of being able to grow almost all winter-growers outdoors. Other people have very limited space, and use the smallest containers possible. Some bulbs will flower in too-small pots, giving flowers smaller than usual, but others will not.

Oxalis can be grown in any container, but you cannot let them dry out in growth. The bulbs are annual. They produce top growth, succulent roots and flowers, but do not produce new bulbs until near the end of the growing season. If you let them dry to the point they exhaust the water in the storage roots before they have formed new bulbs, they are gone. For this reason those of us without time to care for the collection every day tend to use large containers for Oxalis. I use standard "1 gallon" cylindric nursery containers, which are approximately 6" / 15cm tall and wide. If you are certain you won't let them dry out, you can grow very attractive tufts of Oxalis in small bonsai pots.

Some irids, like Moraea spiralis, are miniatures that could flower in tiny pots. Others, like Chasmanthe and Crocosmia, are the size of small haystacks. Again, you need to do some reading or asking about specific plants.

Some bulbs that will tolerate wide, shallow containers would be many small Albuca species; many Cyrtanthus; Oxalis, taking note of what I wrote above; most freesias; some moraeas; some diminutive Gladiolus; Eriospermum; Lachenalia; and small drimias.

Bulbs I wouldn't plant in 3" deep containers include anything growing to be large; Babiana, which will pull themselves to the bottom of the deepest container; many Gladiolus; and almost anything in family Amaryllidaceae, which form long, fleshy roots in profusion. There are a few small Haemanthus that flower well in 3" deep pots.

I sprout my winter bulb seed in 20 or 32 oz foam cups. They are 6" / 15cm deep. The 20s are 3" across. I can't recall the diameter of the 32s.

Leo Martin
Phoenix Arizona USA
Zone 9?

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