Purple Shamrock

November 29, 2010 1 Comment

Shirley posted a question regarding a Purple Shamrock plant that she has in her house.  She said the directions that came with the plant say it is semi-dormant in winter and she would like to know if it needs to be put into the basement for the winter. 

Oxalis regnellii var triangularis is native to Brazil but prefers cool temperatures, especially while in bloom.  Generally it should be at 55-65 degrees (F) at night and not warmer than 75 degrees (F) during the day.  The plant should be fed every two weeks while the plant is growing with a balanced liquid fertilizer that is diluted by half.  When the blooming stops, feed every other month.  The shamrock is a bit different from other plants in that it grows from a bulb.

The shamrock will start to decline in appearance after awhile, but don’t worry. It is the nature of the plant.  Similar to tulips, shamrocks need a dormancy period.  It will come back to life again after the resting period is over.  In many cases people think it is dead and toss it out.  Give it a little time and you should have a flowering houseplant again.

Shamrock plants like to be in an area with bright indirect light.  Keep the soil moist and only fertilize while the plant is still looking vibrant. Eventually the plant will start to go dormant.  Stop watering the Oxalis and let the leaves naturally dry up and fall off.  Don’t pick the leaves off, let them fall on their own.  Once the leaves have done so, move the plant to a cool dark area for a four week dormancy period.  If you have a green leaf variety, it should be left for two or three months, but the purple variety only needs one month of dormancy.  You can bring the plant back to it’s original place, water it, fertilize it and you should have new growth emerging soon!

If you need to repot the shamrock, remove the plant from its pot by tapping the outside of the pot. This will loosen the root ball.  With both hands, massage the root ball to aerate the roots. This promotes future growth. Pick a pot that s one size larger than the old pot.  Make sure it is clean and dry.  Put a rock or broken piece of another clay pot over the drainage hole to keep the potting soil in. Add two or three inches of good potting soil that has some sand mixed in.  This will help with drainage and keep the dirt from becoming a hard clump.  Set the root ball into the soil and fill around the plant with more soil.  Firm the soil around the plant to keep it upright.  Lightly water and then add a little liquid plant food.

Keep a careful look out for spider mites.  Keep the soil aerated and the sickly leaves picked off and the plant should do well. 

While doing my research on this, I came across a web page that talks about oxalis as a whole. The person writing the page was not pleased with the oxalis because the one he or she has in their garden was taking over.  It appears that the purple oxalis/shamrock is not as aggressive, but if you are interested in reading up a bit more on what another type can do, click here.  I seem to recall a plant that I got one year at the end of the season. It was in a pot and I’m pretty sure it was in the oxalis family, but it didn’t have the shamrock leaves.  I left it in the pot and it was apparently a good thing.  I found out it was extremely aggressive, fortunately, not by example.

It was beautiful, but I made sure it didn’t get a foothold in the ground.  It did not come back this past year, so I must have been successful.

As for the houseplant kind, I will leave that to others.  My “boys” would like them too much.

Dig it!

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  1. KD says:

    I love purple shamrock! My mother-in-law gave me a plant about 4-5 years ago, and it is still going strong. In the fall before the first frost, I take the plant inside and put it in a cool, dark closet. I water the plant once a month and I don’t take it out until the spring, after which I put it outside all Summer. Every other year I have to thin it out and take a few of the bulbs out and put them in a new pot to make another plant. I just got a green variety this year and will see how well it does after dormancy.

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