How to Grow and Care for Scarlet Auricula

The Scarlet Auricula is a variety of primrose cherished by collectors for its striking appearance. These plants are distinguished by their vibrant scarlet petals, which often surround a contrasting center, referred to as the “eye” or “paste.” Their compact rosettes of leaves and flowers have secured them a place in horticultural history, making them a rewarding plant for patient gardeners.

Unique Characteristics of Scarlet Auriculas

Scarlet Auriculas are primrose hybrids developed from European alpine species like Primula auricula and Primula hirsuta. They are classified as “Show” auriculas, a group bred for exhibition due to their form and coloration. A notable feature of some Show auriculas is a waxy, white or cream-colored powder called “farina” that can dust the leaves and flowers. This mealy bloom is a natural protection against intense sun and water, adding to their ornamental value.

Their prized status led to the creation of “Auricula Theatres” in the 18th and 19th centuries. These were tiered display stands, often painted black to accentuate the vivid colors of the potted specimens. This history highlights the specialized appreciation these plants have commanded for centuries, showcasing the beauty of each individual plant.

Ideal Growing Conditions

Success with Scarlet Auriculas depends on recreating their ancestral cool, alpine conditions. They require bright but indirect sunlight, as intense midday sun can scorch their leaves and fade the flower colors. A location with morning sun and afternoon shade, like an east-facing wall or under shade netting, is suitable.

Auriculas demand a gritty, well-draining medium, as standard potting soil is too dense. A recommended mix consists of equal parts loam-based compost, peat-free multipurpose compost, and horticultural grit or perlite. The soil should be neutral to slightly alkaline.

Proper watering is a delicate balance. Keep the compost moist but not soggy during the spring and autumn growing season. Water the soil directly, avoiding the foliage and central rosette, as moisture trapped in the crown can lead to rot. During winter and summer dormancy, reduce watering significantly, allowing the compost to nearly dry out.

These plants are hardy and tolerate cold, but not winter wetness. Good air circulation is important to prevent fungal diseases. Many growers use a cold greenhouse, cold frame, or sheltered porch, which offers protection from excessive rain while providing ventilation.

During the growing season, apply a balanced, low-nitrogen liquid fertilizer at half-strength every two weeks. A high-potassium feed can encourage more blooms during the flowering period. Stop feeding once flowering ends and the plant enters summer dormancy.

Planting and Repotting Guidelines

Scarlet Auriculas are most commonly grown in containers. Terracotta pots are a good choice as their porous nature helps the soil dry out more evenly. Select a container that fits the root ball without being excessively large, as this can cause the soil to stay too wet. Ensure the plant’s crown sits at soil level and add a top layer of grit to keep foliage dry.

Repot annually in early summer, right after the flowering period has concluded. This allows you to replenish nutrients and inspect the roots for pests or disease. To repot, gently remove the plant, shake off the old compost, and trim away any dead or decaying roots before placing it in a clean pot with a fresh, gritty compost mix.

How to Propagate Scarlet Auriculas

The most reliable propagation method for a named variety is division, which creates a genetically identical plant. This is best done when repotting after the plant has flowered. New plantlets, or offsets, that have formed their own roots and at least three leaves are ready to be separated.

To divide, gently tease the offsets away from the parent’s main root, ensuring each offset has roots attached. Discard any withered parts of the parent plant. Pot each offset into a small container with the same gritty compost mix used for mature plants. Planting them deeply can encourage new root formation along the buried stem.

Growing from seed is more challenging and does not guarantee the offspring will resemble the parent. Sow seeds in late winter or early spring in a cold frame on the surface of a moist, loam-based seed compost. Germination is slow, requires cool temperatures, and the resulting seedlings will display a wide range of colors and forms.

Common Pests and Diseases

The most significant pests for Scarlet Auriculas are vine weevil grubs and root aphids, which attack below the soil. Vine weevil grubs feed on roots, causing the plant to wilt and collapse. A sign of this pest is being able to easily lift the plant from its pot due to severed roots. Root aphids are tiny pests that suck sap from the roots, weakening the plant.

Botrytis, or grey mould, is a fungal disease that appears as a fuzzy grey growth on foliage, often spreading in damp, stagnant conditions. Root rot is another issue caused by soil that is too wet. Prevention for these diseases includes providing good air circulation, careful watering, and removing dead leaves, as detailed in the growing conditions.