"Shamrock"

 

March 2023

PICKAWAY TO GARDEN

“Shamrock”

By Paul Hang

 

When is a shamrock not a shamrock? Answer: When it is a real rock. OK, I apologize for that one. Sham means a thing that is not what it is purported to mean, false. When trying to write a column for March and St. Patrick’s Day, March 17^th, I thought I’d write about the plant commonly known as shamrock. I was in for a surprise which I thought I’d share.

 

Shamrock was first mentioned in the 1500’s. The Gaelic word is seamrog. St. Patrick was said to have used it as a symbol of the Christian Holy Trinity. It was used as a symbol of the 19^th century Irish Nationalist groups and became a symbol of Ireland itself. On St. Patrick’s Day you will see shamrocks depicted everywhere. You might be tempted to buy a “Shamrock” Plant at a local nursery, grocery store or over the internet for a decoration. Beware! You might be buying a sham shamrock plant. Caveat emptor.

 

What passes for a “Shamrock” plant is probably a type of Oxalis, (also known as wood sorrel). The clover shaped leaves come in shades of green, red, or purple. They may fold up at night or on cloudy days. The flowers, with five petals, borne on long stalks, may be white, yellow, pink or red. Oxalis acetosella has green heart-shaped  “leaves of three.” If you want real shamrocks, leave them be.

 

Another example of sham shamrocks is Oxalis triangularis with, get this, purple foliage and with leaves much bigger than your clover in the lawn. And, it’s from South South America! These oxalis plants are flowering bulbs. Being part Irish, I wanted the real thing.  I figured I needed the Luck O’ the Irish. “Lucky Clover” was advertised with Iron Cross as an example. Oxalis tetraphylla has four green leaves with purple centers and is not a clover. For the care and feeding of these imposters go to: extension.umn.edu.

 

Searching further, I read that white clover, Trifolium repens is the true shamrock. White clover is the diminutive green ground cover with three heart-shaped leaves and little white pompom flowers that used to make up most of our lawns back in the dark ages of my youth. It is commonly considered a lawn weed but lately its popularity is coming back. As luck would have it, (one in ten thousand has four leaves) my search was not over. There is another contender back in the Ould Sod.

 

Lesser Yellow Trefoil or lesser clover, Trifolium dubium is considered to be the true shamrock by roughly half of the Irish people and Trifolium repens (white clover) by another third according to a survey in 1988. Neither are unique to Ireland and both are in the Pea or legume family (Fabaceae) of plants that increase nitrogen in the soil. This is another example of why common names of plants can be confusing and why botanists rely on the Latin names. So, if you want the “real” shamrock, and not the sham, get Trifolium dubium. And, keep this in mind the next time you shampoo the dog. Erin go Bragh.

 

 

 

 

 

 

 

Things to do in the garden:

 

Begin fertilizing houseplants with a weak solution. Now is a good time to propagate houseplants. March may not be too late to try winter sowing. What is winter sowing? It is a way of germinating seeds. Google “winter sowing” for more information.  Have your soil tested. Materials and directions are normally available at the OSU Extension Office.

 

The last average frost date here in zone 6 is April 23^rd. That means there is a 50/50 chance of frost on that date. A number of seeds should be started this month. Check your seed packet for the number of days to harvest and count back to the date you want to plant your seeds or set out your plants. A word to the wise, don’t set out your plants too early unless you are prepared to protect them should the odds work against you.

 

Rake the lawn to remove the twigs, leaves, and other winter detritus. Dig out those biennial weeds before they get established. Now is a good time to plant trees and shrubs and bare root roses. The earlier you transplant perennials the better they will do. When is the soil ready to be worked? Soil that sticks to your spade is too wet to work and will be compacted. Make a ball of soil and drop it. If it crumbles it is ready to work. 

 

Before those buds break, spray fruit trees with dormant oil. Read the directions. Prune damaged, diseased, and dead limbs. Also, prune those limbs that grow inward, suckers and water sprouts. Do not remove more than a third of the tree. Prune deciduous trees and shrubs that bloom in the summer. Prune spring flowering trees and shrubs after they bloom. Prune raspberry canes and grapevines and fall flowering clematis.

 

If you cut back perennials and ornamental grasses (tying up the grasses before cutting them back to about six inches saves a lot of clean up), don’t throw them in the trash or onto the compost pile. Store them until we have a few warm days (temps above 50 F) to give overwintering insects a chance to emerge. Pull back mulch from around perennials on warm days but be prepared to cover them back up if a hard freeze threatens.

 

Late March and April is the time to apply a pre-emergent to the lawn if you want to prevent crabgrass. The best indicator for this is the first bloom of Callery Pear. But be forewarned, pre-emergents prevent seeds from sprouting. Apply pre-emergent on a calm day. There are now selective pre-emergents that do not affect grass seed. If you plan to seed any parts of your lawn, don’t apply a non-selective to those areas. This warning also applies to areas where you plan to plant vegetables and flowers by directly seeding in the soil. A light fertilization of the lawn is all you’ll need.

 

Go to weather.cfaes.osu.edu/gdd for phenology information on when plants flower and insects emerge.