Primroses are hardy ornamental perennials, but like other plants, they do not live forever and are not immune to adverse conditions in the environment.
Pests and diseases can cause the plant to die prematurely. Poor care and neglect can also shorten the life span of the primrose.
With ideal conditions, common primrose (Primula vulgaris) can live up to 5 years; however, factors like pests and diseases can weaken the plant and cause premature plant death if not treated quickly. Evening primrose (Oenothera biennis) does not live quite as long, often fading away after two years.
With proper care, your primrose can thrive and keep blooming year after year. Read more to find out how to protect your primrose from pests and diseases.
Primrose Life Span
As a perennial, you can expect common primrose (Primula vulgaris) to come back every spring after going through the usual dormant period in the winter.
However, many factors impact that life span, and you need to protect the dormant plant in the winter, especially when the soil freezes and could kill the roots.
How Long Do Primrose Plants Live?
You can expect your primrose to live 5 years outdoors. If you plant it indoors, the plant has a shorter life span and will not likely survive past 6 months.
Overwintering is important to the survival of the plant in cold and moderate Growing Zones.
Another plant with a similar name, evening primrose (Oenothera biennis), has a shorter life span of just two years.
Primrose Plant Life Cycle
After germination, the primrose will take a few months to establish. During this time, the plant needs a lot of water to keep up with the fast growth rate.
Once the root ball reaches full development, the flower buds emerge. The plant will go into dormancy in the winter but come back to life in the spring.
Factors That Can Shorten Primrose Life Expectancy
Irregular watering, poor soil, pests, and diseases are all factors that can cut the life of the primrose short. Weather conditions can also hasten its demise.
In colder zones, the dormant plant is prone to dying when the roots freeze over, so overwintering properly is essential for the survival of the plant in these conditions.
Primrose Bloom Time
There are over 500 species of primrose. Some varieties will bloom throughout the year, taking a break in the winter where they go dormant before coming back in the spring.
Others will bloom from midsummer until the first frost in the fall. Then there are primrose varieties that will bloom throughout the winter until the early spring.
Evening Primrose Bloom Time
The evening primrose blooms in the summer until the fall. The flowers open at night since they’re pollinated by night-flying moths and die within 24 hours.
Although wildlife, in general, doesn’t find primrose appetizing, insects think otherwise. Pests will feed on the leaves of the perennial plant and deform their usually green and healthy foliage.
Each type of pest that attacks the primrose requires a different way to deal with it.
Aphids are common in every garden and even around houseplants. They’re tiny and hard to detect. Only when the plant is infested with them would you notice the black, brown, or green dots littering the stems and surface of the leaves.
They penetrate the surface with their mouths and suck the sap and juices while inserting toxins that kill the tissue of the plant. Wash aphids off the primrose with the garden hose, or spray them with neem oil (find it here at a great price).
Caterpillars are a stage in the life cycle of many insects. Primroses are often attacked by the caterpillars of black cutworms and beet armyworms. The first type will feed at night while the other feeds on the leaves during the daytime.
Spray the plant with spinosad or Bacillus thuringiensis to eliminate these pests.
The larvae of leafminers burrow into the leaves and stems of primrose and dig long tunnels causing the tissue to die.
The best way to get rid of them is to cut the affected stems and burn them. If the whole plant is infested with leafminer larvae, uproot the plant and dispose of it safely.
Weevils can cause a lot of damage to the primrose. The adult beetle with its long snout feeds on the leaves and then lays its eggs in the soil. The larvae then proceed to eat through the roots until the plant dies.
Look for cuts in the edges of the leaves of the primrose to identify the weevil infestation, and manually pick the insects and drown them in soapy water.
Whiteflies suck the sap of the primrose and hide on the underside of the leaves. They’re not easy to kill since they fly away when the plant is disturbed.
Use sticky traps (I’ve found that these work very well) to catch them, or cover the soil with reflective mulch.
Primrose is also prone to diseases, and some of them can be lethal. Each infection needs a different treatment.
Botrytis blight is a fungal infection caused by Botrytis cinerea. It covers the leaves near the soil and the dying flowers with a gray layer of fungal growth.
Heat kills the fungus so make sure the plant gets enough sunlight. If that’s not enough, spray the primrose with a fungicide.
This disease is caused by phytoplasma. It stunts the growth of primrose plants and leads to many yellow stems and leaves.
Get rid of the infected plants, and use pesticides to control the pests in the garden that spread the disease.
This is caused by a fungus called Rhizoctonia solani. The disease causes the stems and leaves to turn brown. Flowers fade and die, and the plant won’t produce new flowers.
Remove infected plants, and spray a fungicide to eliminate the fungus.
Primrose Care: Key Tips
- Plant primrose in loamy well-draining soil.
- Water the young plants regularly until they establish.
- Use mulch to improve water retention and keep pests away.
- Apply a liquid fertilizer at half-strength in the early spring.
- Good ventilation and direct sunlight are crucial for preventing fungal infections.
What To Do With Primroses After Flowering?
Once the last flower has faded, primroses will go into dormancy. They need little water and no feeding until the next spring. If you live in cold to moderate climates, you might need to overwinter the plants.
Primrose Winter Care
In cold winters, the primrose is prone to frozen roots, which means that the plant won’t come back in the spring. If you live in a cold region, dig out the plant, and put it in a pot. Keep it indoors until the spring.
In warm Growing Zones where freezing soil is not a threat, cut back the plant to about 4 inches above the ground, and cover it with mulch throughout the winter.
Do Primroses Spread?
Primroses spread quickly and cover the ground. You’ll need to divide them regularly to manage their growth.
Do Primroses Bloom All Summer?
Not all primrose varieties bloom all summer. Some will bloom in early spring while others bloom from midsummer until fall.
Primrose is a perennial plant that can live up to 5 years. Pests and diseases can shorten the plant’s life if not treated in time.
Direct sunlight and good ventilation are important for the plant’s success and will help manage pests and fungal infections.