By Susan Lewitt.
Beach Strawberry, Fragaria chiloensis, in bloom! By John Rusk, licensed under CC BY 2.0.
Have you noticed ice plant all around San Diego? The mats of dry woody material that it forms? Problems with this invasive plant lie in its shallow roots, which don’t help control erosion; the dry woody undergrowth, which is a fire hazard; and the monoculture it forms crowding out more desirable plants including natives.
Another group of invasive plants are ivies. Algerian, Cape, Canary, English, German, and Irish Ivies are major problems because they can harbor non-native rats and snails! They also suffocate understory plants and can endanger and even kill trees with the weight of their vines. Trimmings take root too easily, and should never be discarded in natural areas, or planted near those areas as they will spread. It is also hard to tell the differences between the highly invasive ivies and the more suitable ones, so please just avoid these plants.
Periwinkle, especially Vinca major, may look irresistible, but please avoid this one because it is fast growing and very invasive, forming thick matts. It will root wherever there is soil even if it is only a small cutting and it will crowd out other small plants.
A native flowering plant to consider for ground cover is Common Yarrow, Achillea millefolium, with its sweet fragrance. After its active spring growth period, it will have white or yellow flowers May through June. Then it may be dormant or semi-dormant in the summer. As a moderate to fast grower, it can reach up to 3 feet high and spread about 1 ½ feet wide. It can spread by rhizomes and can be divided every couple years. It can be kept short by trimming it occasionally, but you will miss out on the flowers.
Common Yarrow, Achillea millefolium, in bloom showing height variation. Photo by Susan Lewitt.
Common Yarrow, Achillea millefolium, in bloom. Photo by Susan Lewitt.
Yarrow is found in mildly disturbed soil of grasslands and open forests and is quite easy to grow in full sun to full shade, with any type of soil except wet soil. It can withstand slow to fast drainage, and it may be watered once a week during the summer, when it is established. It is also cold tolerant to about -15 degrees F.
In the past Common Yarrow was used by Native Americans as a medicinal plant to alleviate pain, lower fevers, and for blood issues. It supports carnivorous insects, butterflies, and bees. Some of its visitors include the Yarrow Plume Moth, and the Northern Scurfy Quaker. It works in bird, bee, and butterfly gardens, plus it is deer resistant. It can also be used to control erosion due to its deep roots. It grows well with Lonicera interrupta and Stipa lepida.
Beach Strawberry, Fragaria chiloensis, close-up of flower by Franco Folini is licensed under CC BY-SA 2.0.
Beach Strawberry, Fragaria chiloensis, is another wonderful ground cover to consider and on top of that you get tiny treats! It grows to about 1 foot tall and will spread. It is a slightly fragrant evergreen with white and red flowers blooming winter through spring.
This strawberry fruit is considered a delicacy in south America and it was used to create the modern strawberry, F. × ananassa. It is possible that Hawaiian migratory birds spread this plant to its present range which includes the North American Pacific Coast, Argentina, Chili, and mountains of Hawaii.
Beach Strawberry, which is found in ocean beaches, dunes, and coastal grasslands, will grow in full sun to full shade in fast draining sandy soil, with low or very low moisture. During the summer it may need watering up to 3 times per month. It is quite easy to grow and available at many nurseries.
Beach strawberry works well in bird and butterfly gardens, as a ground cover, and is deer resistant. There are many native plants that work well with this ground cover including Sand Verbena, Abronia latifolia or umbellata, Beach Bur, Ambrosiachamissonis, Beach Morning Glory, Calystegia soldanella, Seaside Daisy, Erigeron sp., Coast Gumweed, Grindelia strict, and other low to the ground coastal natives. It attracts several moth and butterfly species including Filament Bearer, Drab Brown Wave and Clepsis fucana species, plus another possible 32 other species. Native birds enjoy this plant also.
On a personal note, I have a small 3’ by 4’ curb strip patch of mostly natives that have been coming up from seed for a few years. A couple years ago, one side was accidentally sprayed with weed killer by a neighbor. That side now has more weeds, but the seeds I put out are also trying to grow. In this patch there is Yarrow, Blue-eyed Grass, Narrow Leaf milkweed Asclepias fascicularis, Purple Chinese Houses, California Poppies, plus a couple seedlings that are too small to identify. By the time you read this article, I hope all will be blooming! It is amazing how many native ground cover plants you can group together in a small area!
Susan Lewitt has gone through training this summer to be a leader in the Climate Reality Project, a group led by Al Gore, concerned with the health of our planet. This means she will be doing things such as talks, articles, and actions that relate to protecting our environment and slowing down or even reversing the effects of Climate Change.
Susan has been involved in many plant groups but is currently participating mainly in CNPS (California Native Plant Society) as a member of the Conservation Committee and the Gardening Committee. She also volunteers for the San Diego Zoo, currently online only.