Urchin Dahlias are a unique type of dahlia, known for their distinctive appearance. This guide provides information on how to cultivate and care for them.
What Makes Urchin Dahlias Unique?
Urchin Dahlias are recognizable by their distinctive spiky blooms, which resemble a sea urchin. Their unusual, pointed petals are often twisted or quilled, creating a dramatic, textured appearance. The petals can be deeply cut or rolled, contributing to their unique look.
Blooms typically measure 4 to 6 inches in diameter, making them a noticeable feature in gardens or floral arrangements. While specific color variations exist, a common characteristic is a rich, dark red hue, sometimes with purple tips. Their semi-cactus form, with pointed and often rolled petals, makes Urchin Dahlias a striking focal point.
Planting Your Urchin Dahlia
Urchin Dahlias thrive in full sun, ideally receiving 6 to 8 hours of direct sunlight daily. The soil should be well-draining and rich in nutrients, with a pH level between 6.5 and 7.0 (slightly acidic to neutral).
Prepare the planting area by loosening the soil to a depth of 10-12 inches. Incorporate organic matter like compost or well-rotted manure to improve drainage and fertility.
Plant Urchin Dahlia tubers after the last frost, when the soil temperature reaches approximately 60°F. Dig a 4-6 inch deep hole, placing the tuber horizontally with the “eye” or growing sprout facing upwards. Space tubers 12-18 inches apart. Avoid watering immediately after planting to prevent rot; wait until green shoots emerge.
Essential Care for Thriving Urchin Dahlias
Once established, Urchin Dahlias need consistent, deep watering, typically once or twice a week during dry periods. Avoid overwatering, as soggy soil can lead to tuber rot; allow the soil to dry out between waterings. Watering at the base of the plant helps prevent fungal issues and conserves moisture.
Dahlias are heavy feeders but sensitive to high nitrogen, which promotes leafy growth over blooms. A low-nitrogen fertilizer or a bloom-boosting formula (e.g., 5-10-10 ratio) is recommended. Begin fertilizing about 30 days after planting, or when new shoots are 3-4 inches tall. Repeat every 3-4 weeks throughout the growing season for in-ground plants, or every 2-3 weeks for container-grown dahlias.
Taller Urchin Dahlias may require staking to support their stems and heavy blooms. Install sturdy stakes near the tubers at planting time to avoid damage, and tie growing stems to supports as needed. Deadheading, the removal of spent blooms, encourages the plant to produce more flowers. Check plants weekly and remove faded flowers by cutting the stem back to the nearest healthy leaves.
Common pests include aphids, slugs, snails, and spider mites. Aphids can be managed with neem oil or insecticidal soap. Slugs and snails can be deterred with barriers or traps. Spider mites are controlled by hosing off plants or using miticides. Powdery mildew, a white coating on leaves, is minimized by ensuring good air circulation and avoiding overhead watering.
Winterizing Urchin Dahlia Tubers
In colder climates where ground freezes (typically USDA Zones 7 and below), Urchin Dahlia tubers are not hardy and must be lifted and stored indoors for the winter. This process ensures their survival until the next planting season. The ideal time to lift tubers is a few days to two weeks after the first hard frost has killed the foliage and caused the plant to die back and turn black.
To lift the tubers:
Cut the stems back to about 4-6 inches above the ground.
Carefully dig around the plant, at a safe distance to avoid damaging the tubers, using a pitchfork to gently loosen and lift the clump.
After lifting, gently remove excess soil from the tubers and rinse them clean with water.
Allow the cleaned tubers to air dry under cover for several days to a few weeks in a cool, dry, well-ventilated area, away from direct sunlight, to cure them and prevent rot during storage.
Once dry, store the tubers in a cool, dark, and dry location that remains frost-free, ideally between 40-45°F (4-7°C).
They can be placed in cardboard boxes or crates, layered with materials like lightly moistened sand, peat moss, wood shavings, or vermiculite, ensuring good air circulation and preventing the tubers from touching each other.
In very warm climates (Zones 8-11), tubers may be left in the ground if the soil is well-drained and does not experience prolonged freezing temperatures.