The Ascot Rainbow Spurge (Euphorbia x martinii ‘Ascot Rainbow’) is a popular perennial valued for its year-round visual appeal and ease of care. This hybrid spurge is a low-maintenance, drought-tolerant plant that brings distinctive texture to garden spaces. Its unique variegated foliage features a blend of gray-green and creamy-yellow, developing striking red and pink flushes in cooler temperatures, offering color interest even outside of its blooming season.
Optimal Environmental Conditions
Planting the Ascot Rainbow Spurge in the correct location sets the foundation for its success and vibrant coloration. The plant thrives best in full sun exposure, meaning at least six hours of direct sunlight daily. While it can tolerate partial shade, insufficient sun results in less intense foliage colors and a less compact growth habit. The plant is hardy across USDA zones 5 through 9.
Soil drainage is the most important environmental factor for this species. The Spurge will not tolerate soil that stays wet, especially during the winter, which can lead to root rot. It requires sharply-drained soil, making it an excellent choice for rocky, sandy, or gravelly sites. This perennial tolerates poor or lean soil conditions, often performing better than in rich ones.
Watering and Nutritional Needs
Watering
The Ascot Rainbow Spurge is characterized by its high drought tolerance once its root system is fully established. For a newly planted spurge, regular watering is necessary during the first one to two growing seasons to help it develop a deep, robust root structure. Once established, water deeply but infrequently, allowing the soil to dry out completely between applications. Overwatering is the most common cause of decline, as the plant prefers conditions that mimic its arid origins. In extremely hot or dry periods, established plants may benefit from some moisture to prevent stress.
Nutritional Needs
This spurge generally requires minimal supplemental nutrition. It has adapted to thrive in average to poor soils, and excessive fertilizer can encourage weak, floppy growth. If growth appears weak or stunted, a light application of a balanced, slow-release fertilizer in the early spring can provide a gentle boost. For most healthy plants, no fertilization is necessary.
Essential Maintenance and Safety
Maintenance
Routine physical maintenance primarily involves removing the spent flowering stems. After the main bloom period (late spring into early summer), the flower spikes should be cut back to the base of the stem. This practice, called deadheading, helps maintain the plant’s tidy, mounding appearance and redirects energy away from seed production. Cutting the stems back to about six inches in mid-spring, immediately after the flowers fade, can also encourage a more compact habit.
Safety Precautions
Handling this plant requires specific precautions due to the nature of the Euphorbia genus. When a stem is broken or cut, it exudes a milky white substance known as latex or sap. This sap is a known skin and eye irritant, and contact can cause dermatitis or temporary eye inflammation. Individuals should always wear protective gloves and eyewear when pruning or handling the plant. After pruning, all tools and exposed skin should be thoroughly washed, and cut stems should be disposed of carefully to avoid accidental contact.