A Primer on Growing Primrose Flowers (Primula)

Bouquet Perfect™ 'Mandarin' Primrose. Photo by: Proven Winners.

When to plant:

Set primroses out in the garden in spring after all danger of frost has passed. In areas with mild winters, plant primroses in the fall or early winter for late winter and spring blooms.

Where to plant:

Primroses thrive in full sun in areas with cool summers, but usually need partial shade elsewhere. They are ideal for planting under deciduous trees that allow sun to pass through in the spring before the leaves emerge and provide dappled shade during the summer. In hot climates, plant primroses in a location that receives shade during the heat of the day.

How to plant:

Plant so the crown is just above the soil surface, spacing plants 6 to 12 inches apart. To help retain moisture and keep the roots cool, apply a 1- to 2-inch layer of mulch around plants, avoiding the crown.

Soil:

Prefers consistently moist, fertile soil rich in organic matter, with good drainage.

Growing indoors:

In spring, you can find primroses sold as potted houseplants that have been forced for early blooming. Generally, potted primroses will flower for several weeks indoors, after which it is best to plant them directly in the garden or summer them outdoors in their pots.

As houseplants, primroses tend to be short-lived and getting them to bloom again can be challenging, since they require cool growing conditions and a period of winter dormancy. If you decide to keep your primroses indoors, give them plenty of bright, indirect light and place them in a location with nighttime temperatures between 50° to 60°F and daytime temperatures below 80°F.

Watering:

The most important aspect of caring for primulas is making sure they receive consistent moisture. If the soil is too dry, your plants will wilt and shrivel, and if it’s overly soggy, they will be susceptible to crown and root rot. During dry spells, water primroses regularly, providing about an inch of water per week.

Water container-grown plants whenever the top inch of soil feels dry. In hot, dry summer weather, plants may go dormant unless they are kept well-watered.

Amendments and fertilizer:

Because Primula grow best in fertile, well-draining soil, amend it at planting time with compost to improve drainage and add nutrients. Also apply a layer of mulch around the root zone of your plants to help keep the soil moist and insulate the roots from temperature extremes.

In early spring, an application of a bloom-boasting fertilizer for flowering plants will help jumpstart growth. To keep your potted primroses in bloom, feed them monthly using a water-soluble plant food diluted to half strength.

Pruning and deadheading:

To promote new blooms and keep your primroses looking tidy, remove the spent flowers by clipping them off at the base of the stem. Also prune plants as needed throughout the season to remove dead or diseased foliage and to maintain their shape.

Propagating:

The easiest way to propagate primroses is by division, either in spring right after booming or in early fall. Non-sterile varieties may also be propagated by seed, but the resulting plants may not remain true to type. (*See note below on propagating or dividing patented plants. Check your plant tags for the ® or ™ symbol by the plant name.)

Winter care:

Although most primroses are hardy in northern climates, they should be covered with a thick layer of mulch or evergreen boughs in areas lacking consistent snow cover, which will help insulate them from hard freezes and fluctuating winter temperatures. Remove the mulch before the foliage emerges in spring, but protect tender new growth if frost is expected.

Pests and diseases:

Primroses are generally free of pests, but be on the lookout for slugs, aphids, and spider mites. Plants may also be susceptible to leaf spot, a fungal disease characterized by brown spots and yellowing leaves. Remove the infected foliage, and provide adequate spacing between plants to ensure good air circulation.