Many flower families are of more general importance in the rock garden than the evening primrose.
However, few individual species furnish more lively color than some of the members of this family.
The genus is a member of the Onagraceae and is not related to the true primroses.
Opening Of Evening Primroses
Evening primroses do not all bloom in the evening as the name would suggest, and some of those which do will remain open for one or more days.
One of the world’s wonders is the opening of the evening-blooming Oenothera.
First, the calyx begins to crack along one or more sutures.
In a very short time, all that holds the flower imprisoned are a very few minute threads along the edges of the calyx leaves.
Suddenly the threads give way, and the four-petal banners spring open to disclose a long pistil with a cross at the top.
The style runs down far below the flower’s throat to the ovary nestled in the leaves. The anthers dance on thread-like filaments festooned with ropes of pollen.
Soon the night moths appeared, as if by the wave of a fairy godmother’s wand.
Evening-Blooming Primrose Types
Oenothera Albicaulis
One of the most familiar evening-blooming types is Oenothera albicaulis.
The large, white cups take on a flesh tone before closing in the morning sun.
They are frowned on by many people since they have rambling feet, but a 6-inch tile sunken in the ground will take care of this unfortunate trait.
Oenothera Mexicana Rosea
Oenothera Mexicana rosea is often mistaken for Oenothera albicaulis before bloom.
In the South, it might become a nuisance, but in the North, it requires protection to live over the winter.
The blossoms are a lovely shade of pink on opening, and the color deepens during the two or three days they remain open.
Many flower families are of more general importance in the rock garden than the evening primrose.
However, few individual species furnish more lively color than some of the members of this family.
The genus is a member of the Onagraceae and is not related to the true primroses.
Opening Of Evening Primroses
Evening primroses do not all bloom in the evening as the name would suggest, and some of those which do will remain open for one or more days.
One of the world’s wonders is the opening of the evening-blooming Oenothera.
First, the calyx begins to crack along one or more sutures.
In a very short time, all that holds the flower imprisoned are a very few minute threads along the edges of the calyx leaves.
Suddenly the threads give way, and the four-petal banners spring open to disclose a long pistil with a cross at the top.
The style runs down far below the flower’s throat to the ovary nestled in the leaves. The anthers dance on thread-like filaments festooned with ropes of pollen.
Soon the night moths appeared, as if by the wave of a fairy godmother’s wand.
Evening-Blooming Primrose Types
Oenothera Albicaulis
One of the most familiar evening-blooming types is Oenothera albicaulis.
The large, white cups take on a flesh tone before closing in the morning sun.
They are frowned on by many people since they have rambling feet, but a 6-inch tile sunken in the ground will take care of this unfortunate trait.
Oenothera Mexicana Rosea
Oenothera Mexicana rosea is often mistaken for Oenothera albicaulis before bloom.
In the South, it might become a nuisance, but in the North, it requires protection to live over the winter.
The blossoms are a lovely shade of pink on opening, and the color deepens during the two or three days they remain open.
Oenothera Speciosa
Oenothera speciosa has wide leaves sometimes touched with red, and the seed pods have four ridges.
It is sometimes mistaken for Oenothera albicaulis, but the flowers are larger and turn pink with age.
Oenothera Caespitosa
A jewel for the rock garden will be found in Oenothera caespitosa, a native of the high western country.
It forms an evergreen tuft of leaves reminiscent of the dandelion, and the large white flowers are almost stemless.
Oenothera Taraxacifolia
Another similar plant may be called Oenothera acaulis or Oenothera taraxacifolia; the blossoms remain open during the day, and the roots will form dense mats in sandy soil.
Yellow-Flowered Species
A yellow-flowered species which forms tufts of stemless leaves is Oenothera nuttalli.
The underground runners will form mats and should be confined to quarters in the rock garden.
A yellow-flowered species, known as Oenothera walsoni or Oenothera ecristata triloba, makes a welcome addition to the rockery.
It is an annual, or perhaps a biennial in warmer climates, and while it self-sows enough to preserve a good showing, it need never become a nuisance.
The seed pod is almost as decorative as the small butter-yellow blossoms.
The earliest flowers reach down into the heart of the tuft of leaves, each leaving behind a hard three-sided cone for a seed pod.
Each succeeding blossom adds a new cone until, by frost, a large pine-conelike structure is left.
In the early spring, each little compartment opens to throw its seeds for several inches, and a new colony is a horn.
Oenothera Missouriensis
The brilliant Oenothera missouriensis vies with Alyssum saxatile in size and brilliance of color and must be given plenty of space to develop.
When once established, it is extremely hardy and difficult to move.
The blossoms are sometimes as much as 5” inches across and a vivid yellow in the evening.
By noon the next day, they have taken on a deep shade of salmon pink, but there are always plenty more to take their place at sundown.
The papery four-sided seed pods are decorative and sometimes used in Winter bouquets.
Oenothera Fremontii
Oenothera fremontii is a related species that will keep company with the most select rock plants.
The stems are lovely rose in color and are topped with leaves cut from silver satin.
The blossoms are a pale yellow instead of the bold canary of Oenothera missouriensis.
Of course, there is a price to pay for all of this loveliness, as it is neither so robust nor as easily come by as its lusty cousin.
Since it is native to chalky cliffs in dry climates, it detests sticky soils and wet feet.
This is ideal for a scree planting, but it must have perfect drainage and very lean soil in any situation.
The roots are long and easily bruised, and a great deal of care must be exercised in digging and planting them, or they will promptly rot.
A deep hole filled with chipped limestone, sharp sand, and a tiny proportion of light soil will suffice if the drainage is good.
Oenothera Serrulata
Two other native species of the high prairies will take their place with the best rock plants.
Oenothera serrulata is sometimes called primrose willow. It forms a tiny shrublet about 8” inches tall, and the finely-cut leaves may be evergreen.
It is a day-bloomer and is covered from June until late fall with yellow cups about 1” inch in diameter.
Like all Plains children, it hates wet feet and must have limey soil. Scree is even more to its liking.
Oenothera Lavandulaefolia
The other species, Oenothera lavandulaefolia is an evening bloomer, and the petals are connected to form a square-topped tubular flower that is very unusual.
The blossoms remain open during much of the day and turn a deep salmon as they fade.
The roots of this species are tough, making them difficult to establish unless the plants are small.
Try Day-Blooming Primrose Species
For the gardener who wishes lots of yellow in the garden for a nominal amount of money and care, the day-blooming species known as sundrops will answer the purpose and the fussier kinds.
The characteristic Fall appearance of this type is a dark green rosette without any of the fancy scallopings of many other types.
These leaves take on deep reds and russets in winter, making them an added attraction in the rockery.
With the coming of spring, each rosette sends up a stem 6”, 8”, or perhaps 12” inches tall, depending on the diet and moisture.
The bright yellow four-petaled flowers line these stems day after day in June and July.
The rosettes increase by stolons but do not become a nuisance.
Other Primrose Varieties
There are several varieties, but anyone will serve the purpose well.
Oenothera fruticosa is perhaps the most widely planted of these species, and the blossoms may be slightly larger than others.
Oenothera Glauca has grayish leaves in contrast to the hairy green of Oenothera fruticosa.
The flowers are larger than some of the other species.
Oenothera fruticosa variety youngi has smaller blossoms and much larger leaves than the type.
It is a native of the South, and some people use the leaves for greens or “salat” in the southern states.
Any of these may often be purchased as Kneiffia.
Any well-loved plant acquires many “love names” along its history, and the Oenothera is no exception.
It is universally known as evening primrose, but it may also be called:
- Cowboy lily
- Gumbo lily
- Moon-flower
- Evening buttercup
Certain species have acquired names such as:
- Missouri primrose
- Texas primrose
- Rock lily
44659 by Ann Tegtmeier