Oenothera deltoides subsp. howellii Plant Care
Oenothera deltoides subsp. howellii (Munz) W.M.Klein
Updated · Sources · How we source care data
Oenothera deltoides subsp. howellii, the Antioch Dunes evening primrose, is an endangered subspecies of plant in the family Onagraceae, genus Oenothera, and species Oenothera deltoides.
Every 7–10 days
Full sun to partial shade
60–80°F
40–70%
At a glance
How do you care for Oenothera deltoides subsp. howellii?
Water Oenothera deltoides subsp. howellii every 7–10 days, letting the top layer of soil dry out between waterings, and give it full sun to partial shade. It prefers temperatures of 60–80°F (16–27°C) and 40–70% humidity. Fertilize it every 6 months during the growing season.
What Is the Oenothera deltoides subsp. howellii?
Oenothera deltoides subsp. howellii (Oenothera deltoides subsp. howellii) belongs to the Onagraceae family within the Oenothera genus.
Oenothera deltoides subsp. howellii displays an upright, clumping perennial growth habit, reaching up to 3 ft tall with a spread of approximately 2 ft. Oenothera deltoides subsp. howellii produces large, showy yellow or pink blooms that open in the evening.
Leaf size: approximately 4 inches.
How Often Should You Water a Oenothera deltoides subsp. howellii?
Oenothera deltoides subsp. howellii requires watering every 7–10 days. Allow the top layer of soil to dry between waterings to prevent root rot. Reduce watering frequency during winter when growth slows.
Watering Frequency
Every 7–10 days
Let soil partially dry between waterings
What Light Does the Oenothera deltoides subsp. howellii Need?
Oenothera deltoides subsp. howellii thrives in full sun to partial shade.
Light Requirement
Full sun to partial shade
What Temperature and Humidity Does the Oenothera deltoides subsp. howellii Prefer?
Oenothera deltoides subsp. howellii grows best at temperatures of 60–80°F. Oenothera deltoides subsp. howellii prefers humidity levels of 40–70%.
Temperature
60–80°F
Humidity
40–70%
What Soil Mix Works Best for a Oenothera deltoides subsp. howellii?
Well-draining, sandy soil with a neutral pH. Good drainage is essential for Oenothera deltoides subsp. howellii to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Oenothera deltoides subsp. howellii?
Feed Oenothera deltoides subsp. howellii every 6 months during the growing season (spring and summer) with a balanced fertilizer diluted to the strength on the label.
Pause feeding in autumn and winter, when growth slows, and never fertilize dry soil — water first.
Fertilizing
Every 6 months
During the growing season
The PlantoScan app can remind you when to water and when to fertilize each plant.
How Do You Repot a Oenothera deltoides subsp. howellii?
Repot every 2-3 years in early spring. Choose a pot one size larger than the current container, and ensure it has drainage holes to allow excess water to escape.
How Do You Propagate a Oenothera deltoides subsp. howellii?
Oenothera deltoides subsp. howellii can be propagated through seeds, division of root ball. Similar propagation techniques also apply to common evening primrose plant care, which shares the same genus.
Is the Oenothera deltoides subsp. howellii Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Oenothera deltoides subsp. howellii, so we can't confirm whether it is safe for cats and dogs. Keep pets from chewing it as a precaution.
This is a general caution, not veterinary or medical advice. If your pet ate a plant, contact your vet or animal poison control.
See all plants toxic to cats and plants toxic to dogs.
What Pests and Diseases Affect the Oenothera deltoides subsp. howellii?
Oenothera deltoides subsp. howellii is susceptible to aphids, caterpillars, spider mites. Inspect the foliage regularly, especially along leaf undersides and stems. Treat infestations promptly with insecticidal soap or neem oil to prevent spread.
Yellow leaves, brown tips or drooping? See common plant problems and how to fix them.
What USDA Hardiness Zone Does the Oenothera deltoides subsp. howellii Need?
Oenothera deltoides subsp. howellii grows outdoors in USDA Zone 13a. It survives winters down to planting zone 13a. In cooler regions, grow Oenothera deltoides subsp. howellii as a houseplant or bring it indoors before the first frost.
Hardiness Zone
Zone 13a
Keep exploring plants
Oenothera deltoides subsp. howellii is one of many species covered in the complete plant care and identification guide, which groups plants by genus, attribute, and popularity.
It belongs to the Oenothera genus — compare its care with other Oenothera species on PlantoScan.
Oenothera is part of the Onagraceae plant family — browse all Onagraceae genera and species.
Oenothera deltoides subsp. howellii thrives in bright light and direct sun — see other bright-light plants.
More Oenothera Species
Other Oenothera species in PlantoScan's care catalogue share similar watering, light, and soil preferences:
Sources
- Scientific name & taxonomy: Oenothera deltoides subsp. howellii (Munz) W.M.Klein, family Onagraceae (first published in Aliso 5: 180 (1962)) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Oenothera deltoides subsp. howellii, so we can't confirm whether it is safe for cats and dogs. Checked against the ASPCA plant list; any other toxicity note on this page comes from PlantoScan's plant database.
- Hardiness zone: USDA Zone 13a, calculated from the plant's minimum temperature.
- Care values(watering, light, temperature, humidity, soil, fertilizing): PlantoScan's plant database, filtered by automatic plausibility checks — values that fail them are hidden. How we source and check plant data.
Spotted a mistake? Email info@upvision.media with the page link — we check and correct reported errors.
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