Mexican Evening Primrose
Mexican Evening Primrose is a gorgeous accent plant in the spring and summer months. However it is rather unattractive in the winter, since the stems die back after blooming. Not to worry, this plant recovers quickly in the spring. Mexican Evening Primrose is commonly grown in the Southwest as a spring colored plant for several reasons. This plant rapidly grows and can be 6 inches high with slender stems and narrow (1 to 1 1 / 2 inches) leaves. The plant also profusely produces dainty pale purple to rose pink cup-shaped flowers. The flowers bloom in the daylight and do not have any strong fragrance. Also, the Mexican Evening Primrose is only susceptible to the flea beetle. If the foliage begins to thin out consult your local nursery. Mexican Evening Primrose can be used as a border plant, bedding plant, an under-plant, along fences, walkways, in containers, or in rock gardens. It can be used as a ground cover but not recommended since it is not attractive all year long in most climates. This plant looks its best in transitional, natural, desert or wild landscapes. Mexican Evening Primrose looks out of place in formal gardens. Mexican Evening Primrose can be planted from containers all year round and from divisions in the spring. Care should be given when planting so that plants are not planted to close together. They should be planted 2 feet apart for a cover in 2 years or less. If planted closer, the plant will spread quickly and become invasive. Mexican Primrose should be clipped almost to the ground after blooming.
-Jennifer Boyle Agro / Hort 100, Spring 2000
The Mexican Evening Primrose is a spreading plant 12-18″ high, 2-3′ across. With remarkable quantities of pink flowers this plant blooms from early spring to fall. Native to Mexico and Texas this plant will grow in infertile soil, with minimum water, and full sun.
-Matthew Jewett Agro / Hort 100, Spring 2000
Garden Detective: No primrose path in eradicating invasive plant | The Sacramento Bee
We hired a company to landscape the back and front yard last spring. The plants were planted around May 1. In October, I noticed that one of the plants – Oenothera berlandieri – was getting leggy and ugly, growing very large. I decided to get rid of it, so dug it up, not realizing how deep the roots had become.
Four of that plant were put in different parts of the yard. I noticed that some new sprouts had come up in other nearby plant sites. When I called the owner of the business, he said, “Don’t worry; the roots will die when the plant is gone.” I decided to research the Mexican evening primrose and upon Googling it, found out that it is like a weed and can take over your garden. I looked at the other three plants and found they had also sprouted new growth in nearby plant sites. …
I dug out the site where I removed the first plant, going down 10 inches and removing every root I found. It had spread 4 feet by 3 feet. I took out all the soil 8 inches down and put it in a wheelbarrow because I was afraid I had not gotten every single root. … There are two more areas where I got most of the roots out, but I left the soil in the ground. I have one plant still in the ground where new sprouts are appearing as we speak. I need to know what is the best plan of action to eradicate any signs of that plant.
– Joan Conklin, Sacramento
Local News at Your Fingertips
Get unlimited digital access for just $3.99 a month to #ReadLocal anytime, on any device.
According to UC master gardener Anna Symkowick-Rose, the Mexican evening primrose is very difficult to eradicate. Many people choose to place it into landscapes because it is a pretty pink flower that will continue to show beauty for several seasons.
One way to deal with the plant is to keep it but make it more appealing by trimming after each bloom cycle so that it will not appear “leggy.” Full sun exposure and avoiding excess irrigation also helps to keep plants bushy. The more water it gets, the more this usually low-water plant seems to grow.
However, if you want to try to eradicate the plant, here are some suggestions. First, continue doing what you have already done, digging out the plant and sifting through the soil to remove roots in open areas. However, this could cause some damage to other plants. The process will also likely need to be repeated.
If you keep all sprouts cut back, eventually the roots will die due to lack of the plant’s ability to produce food. This could take some time, and would require diligence on your part.
Secondly, the plants could be cut down to a 1- to 2-inch stump that could be brushed with a non-selective herbicide such as Round-Up that will kill anything it comes in contact with. This, too, could kill other plants in the area. (Roses, for example, are very sensitive to Round-Up.) Make sure to follow the application instructions on the product.
In focus: Oenothera
This large and bizarre family has some antisocial members, best excluded from the garden. The bright yellow flowers of Oenothera biennis, which grow on sand dunes and railway embankments, self-seed mercilessly, so avoid it.
The invasive O. speciosa runs through the border and looks like an overblown bindweed in flower (most forms are pink). There are two white forms I would also discount: the scented but very lax sprawler O. pallida ‘Wedding Bells’ and O. acaulis alba, which bears enormous white flowers but produces seedlings that are doppelgangers of dandelions, only hairier.
However, there are two excellent seed-raised varieties that are widely available. Both are sensational in sunny borders, but treat them as annuals and save some seed.
O. ‘Apricot Delight’ is a perennial of upright stance that grows 2ft-3ft in height. It produces large lemon saucers 3in across, which darken and turn apricot as they wither. It is similar in stature and size to O. biennis, but has narrower leaves and warmer coloured flowers, and it is perennial in dry, sunny sites. O. versicolor ‘Sunset Boulevard’ is a short-lived perennial with smaller flowers in warm apricot deepening to red-brown.
There are prostrate oenotheras that tumble over paths and spill out of containers. O. macrocarpa has silvery-green leaves with a distinct silver mid-rib and large flowers, up to 4in across, in soft lemon. This trailing plant loves hot, dry conditions and performs for months. O. ‘Greencourt Lemon’ is particularly lovely.
The best-behaved upright perennial is O. stricta ‘Sulphurea’, which has cream-coloured flowers that darken to apricot, set against dusky foliage. This self-seeds in a well-behaved way, and makes several stems, reaching 2ft-3ft in height. The shorter O. fruticosa ‘Fyverkeri’ reaches 1ft-2ft and has brighter yellow flowers. Its foliage flushes red in hot, dry summers.
O. fruticosa subsp. glauca often has spotted leaves and produces lots of smaller yellow flowers from July onwards. Some forms are grown for their colourful spring foliage, and there is also a new German cultivar of O. fruticosa called ‘Silberblatt’, which has a rosette of darkly spotted silver leaves. But generally oenotheras are not great foliage plants.
Rather, it is their ability to surprise and delight – to pop up unannounced and generously unfurl those wet tissue-paper saucers in sunny colours – that I most admire.
- Oenotheras love sunny conditions and well-drained soil. They are short-lived perennials and usually self-seed (often colonising newly dug areas of the garden) – but always save some seed as a precaution.
- Seeds can be sown in loam-based compost and germinate easily in warm conditions (65F-80F or 18C-27C). Seedlings take less than a month to appear. Spring sowing is most effective.
- Prick out seedlings individually into 3in pots, then plant out while they are still young – many plants have taproots that resent disturbance.
Where to buy
Seed suppliers: Plantworld (01803 872939), which is offering a free packet of Oenothera ‘Apricot Delight’ with every catalogue.
Thompson & Morgan (01473 688588); and Unwins Seeds (01945 588522).
Beeches Nursery, Ashdon, near Saffron Walden, Essex CB10 2HB (01799 584362, www.beechesnursery.co.uk).
For ‘Greencourt Lemon’, try Green Farm Plants, Bury Court, Bentley, near Farnham, Surrey GU10 5LZ (01420 23202).
Some members of the evening primrose family are more capable of, shall we say, spreading than others and I had several that were quite well behaved. If it makes you feel any better I did something along the same lines when looking for something to fill in a hot and dry spot at the edge of a newly created garden. I saw the label, had good experience with the other plants from the same family in a previous garden (different zone where this one does not make it) and with a label that read “easy to grow” and “attractive to bees and butterflies” I decided to give it a whirl.
Fast forward to the end of the summer and I began finding new plants popping up 3 feet away and choking other plants in between. When I pulled them up they came up with lots of runners. I followed the runners back to the main plant and realized I had a problem. I looked it up and to my dismay found it is invasive as all heck in many places. I immediately yanked the main plant and began uprooting any and all shoots. Thank goodness I have well amended soil so that I could easily pull them, but it still took another year of “weeding” to eradicate new seedlings from the old roots or seed. Some people do it for longer from what I have seen.
To give you an idea at how tough these things are I’ve since found them growing along the highways in Alabama out in the blazing southern summer sun in drought conditions, and they are happily spreading out. Pull now and expect to keep pulling it out for the next year or two. Don’t forget to tell anyone you meet NOT to buy it unless they have a piece of garden that is not near any other plants they value.
Here in the West, we have numerous members of a wonderful group of drought tolerant native flowers, many of which are hard to find, or altogether overlooked. These plants can take partial shade or brutal full sun, require only occasional watering, propagate easily, and bloom profusely in the evenings and early mornings. Several of the species are evergreen, and provide an attractive green ground cover whether they are in bloom or not. Additionally, they provide a source of nourishment to a different subset of nectar feeders than many of the other flowering plants, these are from the family Onagraceae, genus Oenothera, evening primrose. Other names for members of the group include Sundrops and Flor de San Juan.
General characteristics of Oenothera are that they can be annual, biennial, or perennial. Blossoms are white, pink, yellow, have four petals, four sepals, eight stamen and a four-celled seed pod forms against stem. The blossoms tend to be from two to four inches in diameter, and the plants can be from six inches to five feet tall. They range in altitude from sea level to 9,000 feet, but are most common from 1,000 to 7,000 feet. Cold hardiness varies but is usually to about 10?F.
Evening primrose has been used historically for medicinal purposes, and recent clinical studies indicate that the oil of evening primrose is high in Gamma-linolenic Acid (GLA) and is useful in regulating fatty acids, reducing hot flashes and PMS, and improving eczema and psoriasis (when used topically). Other studies concerning use in some types of heart disease look promising, but it’s too early to tell.
Did you know that 21 native Oenothera have been documented in Arizona alone? In a good year, you may find three Oenothera species plants available locally. Most likely the Baja (O. stubbii), Mexican (O. berlandieri) and Missouri (O. missouriensis). All are great in full sun, but a little extra late afternoon or morning shade allows longer enjoyment of the blossoms. All three are attractive low water use ground covers. The O. stubbii and O. missouriensis have large yellow flowers. I have killed both Missouri and Baja primrose plants by overwatering. I now put four to five different low water use plants, including a couple of Missouri tubers, in an area served by a half gallon drip.
The Mexican evening primrose (O. berlandieri) is perhaps the best known of the desert southwest Oenothera. This plant is a living contradiction. It is amazingly drought tolerant, surviving on just natural precipitation in some of the local microclimates. In others, minimal watering is enough, yet it produces abundant, very delicate pink blossoms. A little additional water results in a profusion of pink, which can last much of the spring, summer and into the fall. Propagation is easy. I keep a one gallon container and divide it twice a year. Plant two thirds, repot a third. Just add a little water and the plant does the rest. It makes a nice evergreen groundcover and bronzes slightly in the winter. If given more water than it needs to survive, it can become invasive.
My recent enjoyment has been from three native primroses that have voluntarily appeared in the yard. Two were recognizable because they had the classic evening primrose lanceolate leaves. One turned out to be Prairie evening primrose (O. Albicaulis) and the other, which I’m still researching, has beautiful large yellow blossoms on a six inch plant and seems to be perennial. The third has been an amazing experience. When it appeared in the yard, it didn’t look like anything I’d ever seen before. It did not have classic primrose lanceolate leaves or gray-green color. For two months it grew taller and put out radial branches. I cut back one side of it as it was blocking the sun of several other plantings. Finally, over Fourth of July weekend, it bloomed just before sunset. What a knockout! At the end of each of 12 or 15 remaining radial branches, two to four lemon-yellow blossoms opened, and at the top of the five foot center spike, four to six bloomed. They were about three inches in diameter and smelled like plumeria, but not as strong. Several hummingbird moths gorged themselves on the nectar, their feeding tubes caked with pollen. There was a repeat performance each evening. The plant turned out to be Hooker’s evening primrose (O. hookeri), a biennial. I hope to have seeds to share in early September.
Sources of native primroses are hit or miss. Mexican evening primrose, and occasionally Baja or Missouri, can be found at Ace Garden Place in one gallon pots. Missouri can be ordered, for as little as fifty cents a tuber, from catalogues like Fields and Gurneys and will survive here. (Don’t order them in the late summer unless you can handle wintering them over in a cold frame or microclimate which will allow them a fighting chance to establish during our colder months. Mine arrived in November having broken dormancy during shipping. Between that shock and the puppy getting into the make-shift cold frame and trying them as chew toys about half survived.) Plants of the Southwest in Santa Fe, NM has seed available for 5 different evening primrose, not including the Mexican. White Flower Farms had plants of two species (O. fruiticosa glauca ‘Solstice’ and O. Speciosa ‘Rosea’) in their spring 1998 catalogue. Shepherds has seeds for one (O.Pallida).