St. Patrick’s Day Story
The history of Saint Patrick’s Day does really include what the Irish call a green clover, or shamrock. Saint Patrick was said to have bent down and picked up a leafy green shamrock stem found on the church lawn one Sunday morning. He then brought it inside and used its three leaves on one stem to explain the Holy Trinity in his sermon.
The shamrock is actually a common name for oxalis, or wood sorrel. It is often called shamrock, but is also referred to as yellow wood sorrel, and as good luck plant. However, a homeowner with oxalis springing up on the lawn would not consider it to be lucky. Due to the invasive or aggressive nature of shamrock plants, it is a better idea to just use them as indoor plants. They like the Florida environment too well.
The yellow oxalis, or wood sorrel, is considered a weed. There are six varieties of oxalis in Florida, some native and some not. The pink ones are sold in nurseries and are originally from tropical America. They have escaped cultivation and are considered to be invasive also. While they are now not supposed to produce seeds, they are still capable of spreading by rhizomes. While some nursery cultivars have classic green leaves, others have purple leaves.
A purple leaf cultivar creeping in a local garden – photo S Switek
Why we should not plant Shamrock?
- Unfortunately, yellow oxalis is one of our worst weeds. It springs up in lawns, disturbed areas, gardens, flowerpots, nurseries, and along woodland trails.
- It likes moist areas but can live in dry areas too.
- It grows vertically but can easily begin to grow horizontally after mowing, which does not bother it at all.
- It spreads by rhizomes underground, and by exploding seed capsules above ground.
- The seed capsules can be propelled at 16 feet. One plant can produce 5000 seeds a year, and the germination rate is near 100%.
- New plants often have a reddish tinge to the leaves when they first appear.
- Underground, the buds and nodes on the rhizomes are constantly spreading.
The next question is a strange one considering Saint Patrick’s Day. How do you get rid of oxalis in your yard?
- It is not easy to kill.
- The first option listed is of course the hardest one, which involves hand pulling when the soil is moist. It is never easy, and pieces of rhizomes must not be left in the ground.
- Second option, herbicides are often used on lawns. However, some cannot work if there are underground parts of the plants which have no leaves on the surface.
- When using herbicides read the label and follow the directions.
- Keep in mind that oxalis is a perennial and will surely reappear and recover after any cold weather.
- You will certainly want to treat it before the flying seed pods appear.
- Do not rototill anywhere that oxalis is growing, as this just disperses rhizomes and stems, each of which will start a new plant.
So, here in Florida it appears that a good way to celebrate Saint Patrick’s Day would be to just wear something green. Even the nursery cultivars will eventually require some digging as they spread through your flower bed and surrounding area. Though some cultivars can be somewhat attractive, oxalis is better indoors.
Need more information:
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By: Sandy Switek since 2005 and Eva Maria Pabon Residential Horticulture Agent
Do you want to read more about gardening? Follow our blog Eva Pabon, Author at UF/IFAS Extension Osceola County (ufl.edu)