Oenothera Macrocarpa: How To Grow Evening Primrose

Oenothera macrocarpa, additionally recognized by its widespread title Missouri night primrose, is a low-maintenance herbaceous perennial with beautiful yellow flowers and slim grey-green leaves. 

They make a stunning addition to wild gardens and native plant gardens. Their shiny yellow flowers earned them the Royal Horticultural Society Award of Backyard Benefit. Since they’ll survive in poor soil, together with rocky prairies, clay soil, and limestone glades, they’ll additionally add curiosity to rock gardens with dry soil the place different vegetation could battle to develop. 

Missouri night primrose is most simply recognized by its shiny yellow flowers, that are the dimensions and form of teacup saucers. Like all members of the night primrose household, the flowers open within the late afternoon into the next morning. Because of this, they’re pollinated primarily by nocturnal bugs like hawk moths and sphinx moths. 

Including them to your native panorama offers a much-needed meals supply for nighttime pollinators, even once they’re potted vegetation. One other advantage of Missouri night primrose is that it flowers over a protracted time frame. Their bloom time stretches from spring to mid-summer. 

These native flowers open earlier than many others within the spring. When the flowers die again within the late fall, they may type seed pods amongst their foliage that may readily self-seed and unfold over time. The stems and leaves path alongside the bottom in a spreading development behavior, making them the proper floor cowl. 

Fast Care Information

Oenothera macrocarpa. Supply: Allen Gathman
Widespread Title Missouri night primrose, bigfruit night primrose, night primrose 
Scientific Title Oenothera macrocarpa
Household The night primrose household, Onagraceae
Peak & Unfold 10 inches tall and as much as 24 inches huge
Mild Full solar to mild shade
Soil Rocky or sandy soils
Water Drought tolerant
Pests & Illnesses Slugs, root rot, deer resistant

All About Oenothera Macrocarpa

Oenothera macrocarpa foliage and flowers
Oenothera macrocarpa foliage and flowers. Supply: CAJC within the PNW

As talked about above, Missouri night primrose is well-known for its slim inexperienced leaves and showy yellow flowers that bloom profusely all through the late spring and into mid-summer in rock gardens, clay soil, and limestone glades. The flowers are on the bigger facet at 4 inches huge, and every flower blooms for at some point. 

The genus title entails two root phrases – oeno, or donkey, and thera, or lure – which discuss with its capability to offer an area for donkeys to relaxation for a second. It has another botanical title and is also called Oenothera missouriensis. It has many a typical title, with bigfruit night primrose and Ozark sundrop amongst them.  

Night primroses are named as such as a result of the flowers solely start to bloom within the late afternoon and stay open till the next morning. Throughout their bloom time, they emit a mildly aromatic scent that draws nighttime pollinators similar to hawk moths and sphinx moths. The yellow flowers stand in distinction to the attractive inexperienced foliage alongside a number of brief crimson stems that sprawl throughout the bottom. 

Perennial Missouri night primrose is native to virtually the remainder of the US, in components of Mexico and Central Southern United States like Texas, Oklahoma, Arkansas, Kansas, Nebraska, Missouri, Illinois, and Colorado. It’s particularly prolific all through Missouri, particularly within the Ozarks. It’s there these showy vegetation develop about 10 inches tall and unfold.

The world with probably the most species of this native plant is the southwest of the US, and there are species of the Oenothera genus in each state aside from Alaska. This perennial Oenothera missouriensis plant can tolerate warmth and drought and in addition survive via chilly fall months and winters to come back again within the spring. 

Missouri Night Primrose Care

Missouri evening primrose flowers
Missouri night primrose flowers. Supply: amy_buthod

Missouri night primrose produces lovely and showy 4-inch huge pale yellow flowers amongst its beautiful inexperienced foliage. When grown in its native habitat, Oenothera missouriensis is low upkeep and drought tolerant. 

Solar and Temperature

Missouri night primrose does greatest in full-sun backyard or yard areas that obtain at the very least 6-8 hours of daylight per day. Their native habitat is concentrated in areas of USDA rising zones 4-8. These areas expertise true 4 seasons with chilly winters and sizzling summers. Essentially the most energetic interval of development happens throughout their ideally suited temperature vary, between 70-85 levels Fahrenheit. 

In areas with sizzling summers, as soon as temperatures are constantly above 85 levels in late spring or early summertime, the expansion fee will decelerate, and showy flowers of Oenothera missouriensis could drop quickly. To keep away from this, in case you dwell in an space with excessive warmth, then planting Oenothera missouriensis in mild shade – or at the very least an space the place there’s morning solar and afternoon shade – is the higher choice to get probably the most out of your night primrose even via the warmth of the summer season. 

This perennial plant species will go dormant, and the leaves will die again within the winter and revive within the spring from self-sown seeds and taproots to develop tall and flower in summer season.

Water and Humidity

As with most outside vegetation, water early within the morning or late afternoon to keep away from dropping moisture to evaporation in the course of the warmth of the day. In case you neglect to water at nightfall, wait till the next morning. You’ll have to water frequently in the course of the first season of development to assist set up your native vegetation and their flowers, at the very least 2 occasions per week. 

Within the second yr of development. It’ll grow to be extra drought-tolerant and might be watered 1 time per week. By the third season of development, they are often watered as soon as each 2 weeks. Missouri night primrose prefers dry soil, so it’s higher to underwater than to overwater. 

Make sure you keep away from watering the leaves and planting in waterlogged websites, like close to a downspout or low-lying space in your backyard, particularly within the winter with accumulating snowfall. An excessive amount of moisture could injury the roots and trigger different points, similar to root rot.

Oenothera Macrocarpa Soil

Base of primrose flower
Base of primrose flower. Supply: mccormacka

Except for its drought tolerance, one other profit to including Missouri night primrose to your panorama is that it could tolerate poor soil and stay its showy self. This implies the planting web site doesn’t essentially must be amended in any method. Oenothera macrocarpa species thrive in dry clay or rocky soils and are normally present in limestone glades or rocky prairies of their native habitat. This makes them completely fitted to rock gardens, however additionally they flower nicely as potted vegetation. 

When rising in containers, the kind of soil combine will not be essentially as essential as offering your Oenothera species of vegetation with well-draining soil. Including perlite to a normal potting combine might help enhance drainage. As talked about above, constant soil moisture could cause points with these leaves and their mildly aromatic yellow flowers. Their most well-liked soil ph vary is impartial to barely acidic.

Fertilizing Oenothera Macrocarpa Vegetation

Missouri primrose is a sexy alternative as a perennial flower as a result of it’s very low upkeep. It might survive and flower on little or no water, tolerates all kinds of soil varieties, and doesn’t require any common fertilizer or soil amendments. They really desire lean soil reasonably than wealthy fertile soil. This goes for each the plant and newly germinating seeds.

Though fertilizing isn’t needed, this plant species can profit from the enhance of a layer of compost on the planting web site, though this isn’t a should. You might also topdress with compost at first of every rising season within the early spring, however macrocarpa will proceed to develop, flower, and unfold regardless. 

Pruning Missouri Night Primrose

It’s not essential to prune your night primrose flower, however it may be helpful in serving to comprise it. This perennial species might be reduce to some inches tall simply after they bloom in early summer season as a way to forestall them from going to seed and additional spreading. 

In case your objective is to make use of Missouri primrose as a floor cowl over a big space, you could select to forgo pruning altogether and let it develop wild! To keep up the general well being of your primrose, it’s greatest to chop again outdated development within the early spring to a top of 6 inches tall earlier than new plant development seems. In the course of the early summer season, deadhead spent blooms to encourage much more showy yellow flowers.  

Oenothera Macrocarpa Propagation

An Oenothera macrocarpa plant will voraciously self-seed. If the intense and showy yellow flowers are left standing on the plant after their bloom time on the finish of the season, they may die again and type seed pods. The seed pods might be left to unfold seeds on their very own, or the seed might be collected for extra purposeful sowing elsewhere within the backyard. 

Cuttings are additionally an choice if you want extra Missouri night primrose even quicker. Take a plant chopping just under a leaf node and take away the decrease foliage. Place this chopping in a glass of water, and roots will type over the subsequent few weeks. As soon as measurable root development has fashioned, your macrocarpa vegetation might be planted out.  


Evening primrose as a wildflower
Night primrose as a wildflower. Supply: cultivar413

As talked about above, Missouri primrose is usually pest and illness free! There are, nonetheless, some issues to be looking out for. 

Missouri Night Primrose Rising Issues

Most rising issues stem from a lack of daylight. In case you discover that your night primrose will not be producing yellow blooms and subsequent seeds, it could want extra daylight. To keep away from having to dig up and transfer your primrose, comply with planting directions in your particular location. 

In areas with very popular summers, they’ll profit from being planted in mild shade. In most different areas, they like to be grown in full solar. These native vegetation don’t do nicely in shaded areas.  


One other nice advantage of including Missouri primrose vegetation to your panorama is that they haven’t any severe pest points and are deer resistant. That being mentioned, slugs and snails can sometimes chomp on the foliage in spring and early summer season, however they hardly ever trigger something apart from superficial injury. 

If the injury turns into extreme, they are often handled with slug and snail bait generally discovered at huge field shops and {hardware} shops. Observe the instructions on the bottle for utility. In case you’re searching for a extra pure different, you may wish to attempt beer. Slugs and snails have a recognized attraction to beer. Fill a container with beer, bury it in order that the lip of the container is at soil degree, and slugs/snails will fall in and be unable to get again out. 

You might have to take care of birds utilizing the seed as a noon snack. In case you’re fearful about dropping seed to birds, you possibly can cowl your vegetation with shade fabric or accumulate the seed as they arrive out of the pods. Then you possibly can sow the seed beneath cowl of sediment to discourage birds.


Root rot is the principle illness that may have an effect on your native Missouri primrose. Root rot is mostly brought on by saturated soil from over-watering. The signs of root rot will seem as a mushy mushy stem, wilting, and naturally, rotten roots. One of these rot is more durable to get well from however might be remedied if there are nonetheless recent, white roots on the plant that haven’t but turned to mush. 

In case you’re rising in a container, reduce the rotted roots and plant them right into a pot of dry soil. When grown within the floor, again off of watering your plant and let the encircling soil fully dry out earlier than watering once more. In case your night primrose was planted in a web site that turns into simply waterlogged, you may have to dig it up and transplant it to an space with higher drainage, with sandy or clay soil. 

Regularly Requested Questions

Blooming bigfruit primrose
Blooming bigfruit primrose. Supply: plantpollinator

Q: Is Oenothera macrocarpa invasive?

A: Missouri night primrose will not be technically thought of to be invasive. Nevertheless, it does unfold aggressively and is a prolific perennial self-seeder. 

Q: How do you develop Oenothera macrocarpa?

A: These vegetation do greatest in lean clay or sandy soil positioned in full solar.  

Q: How do you take care of Oenothera?

A: Water frequently throughout its first rising season to assist the plant set up itself. Throughout its second rising season, it would grow to be extra drought-tolerant. 

Q: Do night primrose entice bees?

A: The brilliant yellow flowers entice many pollinators, together with bees, however as a result of they have an inclination to bloom within the late afternoon and into the night, they’re pollinated primarily by hawk moths and sphinx moths.  

Q: Does night primrose come again yearly?

A: Sure, night primrose is a perennial plant in USDA zones 4-8. 

Q: What grows nicely with night primrose?

A: Since Missouri night primroses unfold alongside the bottom, they make an important addition to an space of the backyard that wants perennial floor cowl. Of their native habitat, they develop in giant clumps in meadows and sandy or rocky prairies. 

Q: The place ought to I plant night primrose?

A: They need to be planted in a full-sun location. 

Q: Must you reduce night primrose?

A: In case you want to forestall its aggressive unfold, reduce your night primrose after the blooms are spent however earlier than the seed pods have fashioned. 

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