Hostas are popular shade perennials, prized for their lush foliage and ability to thrive in difficult areas. When people speak of a “purple hosta,” they are usually referring to cultivars where the purple color is concentrated in the petioles (leaf stems) or in the flower scapes and blooms. While the leaves may be deep green or blue, the striking contrast of the burgundy-to-black-purple stems creates the visual effect of a purple plant. This coloration is due to anthocyanin pigments.
Selecting the Ideal Site and Variety
Purple hostas require a specific light regimen to develop their best color. The ideal location provides bright, indirect light or a few hours of gentle morning sun. This controlled exposure stimulates the production of purple pigment in the petioles and scapes without scorching the leaf blades. Deep green or blue-green leaves, especially those with thin substance, can easily burn if they receive harsh midday or afternoon sunlight.
Cultivars like ‘Purple Heart’ are bred for deep maroon to black-purple petioles, with the color often extending into the leaf base. ‘Red October’ is another excellent choice, featuring narrow, blue-green leaves and deep purple stems that intensify as the season progresses.
The location should also be protected from strong winds, which can shred the large, tender leaves. The site must have excellent drainage, as hostas are highly susceptible to crown and root rot if their roots remain saturated.
Essential Planting and Soil Requirements
Hosta health begins with the soil, which should be rich in organic matter to provide nutrients and retain moisture without becoming waterlogged. A neutral soil pH, ideally between 6.5 and 7.5, is suitable for optimal nutrient uptake. Incorporating well-rotted compost or leaf mold into the planting hole improves soil structure and fertility.
Proper drainage is essential, as standing water quickly leads to fungal issues like root rot. If the soil is heavy clay, plant the hosta slightly higher than the surrounding grade or amend the bed with coarse material to facilitate water runoff.
When planting, the crown (where the roots meet the leaves) should be positioned exactly level with the soil surface. Planting the crown too deep invites rot, while planting too shallow causes roots to dry out quickly. Adequate spacing, typically 18 to 36 inches depending on the variety’s mature size, ensures good air circulation and helps prevent foliar diseases.
Water, Fertilizer, and Enhancing Purple Coloration
Deep, consistent watering is fundamental, especially during dry periods, to encourage a robust root system. Water thoroughly once or twice a week, allowing the water to soak into the root zone, rather than using frequent, shallow sprinklings. Applying water directly to the soil beneath the leaves is preferable to overhead watering, which can contribute to leaf spot diseases.
Fertilization should be handled with restraint. A balanced, slow-release granular fertilizer applied once in early spring as the new pips emerge is generally sufficient. Use a formula with low nitrogen content to support foliage growth without encouraging soft tissue that is vulnerable to pests. Over-fertilizing can lead to salt buildup and decrease the plant’s overall hardiness.
The vibrancy of the purple coloration is directly influenced by light and moisture management. Maintaining even moisture levels helps the plant remain healthy, which supports the visual prominence of the colorful petioles. Controlled stress, such as slightly cooler temperatures and specific light exposure, can enhance the concentration of these pigments, making the purple stems more dramatic.
Managing Common Hosta Pests and Diseases
Hostas are susceptible to damage from slugs and snails, which feed on tender leaf tissue, leaving holes and silvery slime trails. Non-toxic control methods are highly effective for managing these pests, and applying these controls consistently prevents significant defoliation throughout the growing season.
These methods include:
- Copper barriers, as the metal reacts with the pests’ slime to give them a mild shock.
- Hand-picking pests in the evening or morning.
- Shallow containers of beer placed at soil level to act as traps.
- Diatomaceous earth sprinkled around the base of the plant, creating microscopic barriers that deter soft-bodied pests.
A more serious concern is Hosta Virus X (HVX), a viral infection causing mottling, discoloration, or distorted leaf growth. There is no cure for HVX, and its presence weakens the entire plant. Since the virus spreads through infected sap, usually via unsterilized tools during pruning or dividing, strict sanitation is the only preventative measure. Any hosta suspected of having HVX should be immediately removed and destroyed to prevent spreading the virus to nearby healthy plants.