Tuesday, May 27, 2014

Plant Portrait - Oxalis adenophylla


Most of the wood sorrels (Oxalis) are not very hardy. This is one of the few that can survive very cold winters unprotected (hardiness zone 5). It hugs the soil, reaching about 12 cm (4 in) high. Given the size of the plant, the purplish pink, funnel-shape flowers with dark veins are relatively large at 2.5cm (1 in).  The crumply leaves are grey-green, divided in many segments arranged finger-fashion. The common name, silver shamrock, refers to the colour of the foliage. Both the flower and the leaves fold up at night or in overcast weather and are said to "go to sleep".




Although it comes from Chile and Argentina, in its native habitat it grows on mountain slopes where temperatures get quite cold.  This explains why it can put up with cold winters (including 2013-14, one of the coldest on record when the thermometer went down to -35 C at Roche Fleurie). The important factor that allows this sorrel to survive till spring is to grow it in well-drained or sandy soil. We grow it in a raised bed where there is rich soil at the bottom but the top layers of the bed are sandy. We grow it in full sun. I notice that writers who live where the sun is not as strong (Britain) insist that it be grown in full sun. Those who live where the sun in stronger say it can tolerate some shade.

The bulbs are unusual looking in that they are very hairy and completely surrounded by a lot of fibrous material reminiscent of strands of coir. The bulbs should be planted just below the surface, and so some of the fibres stick out the ground (see the middle flower in the top row in the picture below). I would cut off all this fibre before planting the bulb if I were to do it again. The plant forms clumps and the leaves come out of the ground all bunched up and then proceed to spread out in bright sunshine. The flowers appear a few days after the leaves in late spring.





It is a very attractive, easy to grow bulb. The foliage is as interesting as the flower. It needs good, but well-drained soil. As long as it gets enough sun and does not sit in water in winter, come late spring, it blooms beautifully. Apparently it is easy to increase by dividing the bulbs in the off-season.

If it is kept in a cool greenhouse, it will bloom in winter. Here are a few of the plants that are in bloom at the same time as Oxalis adenophylla at Roche Fleurie :

Primula auricula
Potentilla neumanniana 'Verna'


Speedwell 'Georgia Blue'
Veronica umbrosa 'Georgia Blue'



12 comments:

  1. It is funny how some of these very delicate looking flowers are actually quite tough.

    ReplyDelete
  2. The foliage is very interesting, I like it. So, spring is arriving up your way, too?

    ReplyDelete
  3. This is such a pretty Oxalis with lovely leaves. The very word Oxalis fills me with horror because of a losing battle with Oxalis corniculata. And I have noticed that in Mediterranean countries the Bermuda Buttercup: Oxalis pes- caprae is an even worse pest. I can' t imagine this dainty little plant having ambitions to take over the world though.
    Spring has been and gone here. What we have is summer. Well summer flowers, if not weather.

    ReplyDelete
    Replies
    1. I suppose I should be glad I have never seen Oxalis corniculata. It looks pretty enough. As for the weather here, as is the case in the majority of years, a couple of weeks ago you were careful to shut the door quickly to keep the warmth in, we are still quick about it but now it is to keep the cool in! Two weeks ago fields were flooded all around us, for the last 3 days I have been watering every night!

      Delete
  4. Truly, a lovely little plant, amazing how they survive on the mountain tops.

    ReplyDelete
  5. Lovely plant! I think of oxalis as shamrock, but this is a much prettier flower.

    ReplyDelete
  6. I have quite fallen in love with my Creeping Veronica. I thought that its Latin name was Veronica peduncularis, but it looks just like yours. Mine is "Waterperry Blue" and I have another one named "Blue Eyes" which is a lighter blue. Both are in full bloom now and make a carpet of blue through which the daffodils rise up.
    The battle against the Oxalis corniculata is never ending.
    I have grown the tender Oxalises both the white flowering ones and the deep burgundy leafed ones, but I do like your hardy wee one.
    Helen

    ReplyDelete
    Replies
    1. I also have Waterperry Blue. Aren't they nice these Veronicas? They do self seed though and have to be watched.
      I grew the deep burgundy Oxalis last year but did not take it in in the fall. I got the bulbs for Oxalis adenophylla at Ontario Seed (close to you). I used to grow it in our old garden and I got it again last fall. It is a lovely little plant but the sun has to be very bright for it to open. The moment there is a cloud, they close until the sun returns.

      Delete
  7. Your oxalis is a sweet little thing. I have to admit I don't know much about them. Just got one with dark red foliage and pink flowers of a friend who has it in her garden and I like it a lot. Thanks for sharing your views on Chelsea. Bet you have lots of flower shows too - wonder whether they're the same or more sustainable.

    ReplyDelete
    Replies
    1. Ours are not more sustainable. The one in Toronto was quite impressive the first 2 years or so (there would be magnificent displays by the Niagara School of Horticulture for instance) but I expect it was too expensive as for at least 10 years now it is much simpler and really geared to garden businesses. There is a large flower arrangement section, which adds a nice non-commercial component to it, even if this type of arrangements has a very tenuous relation to gardening.

      Delete
  8. The foliage is very decorative, it has original texture.

    ReplyDelete

Thank you for leaving a comment