The ‘Blue Skies’ Lilac (Syringa vulgaris ‘Blue Skies’) is a popular ornamental shrub, cherished for its distinctive lavender-blue flowers and sweet fragrance. This deciduous plant adds classic appeal to any garden, offering both visual charm and an aromatic presence.
Understanding Blue Skies Lilac
The ‘Blue Skies’ Lilac is a French hybrid known for its reliable performance and captivating features. This upright deciduous shrub typically reaches a mature height of 8 to 10 feet and spreads 5 to 8 feet wide, forming a full, rounded silhouette. Its bloom time occurs in mid to late spring, often around mid-May, showcasing panicles of pale lavender-blue, single flowers. These blooms emerge from lilac-pink buds, covering the shrub in a bicolored display that is visually appealing and highly fragrant.
The sweet scent attracts pollinators like butterflies and hummingbirds. Its heart-shaped, light green foliage remains attractive throughout the summer, providing consistent garden structure. This variety is notable for thriving in warmer winter areas, as it requires only a light winter chill for buds to mature and bloom, unlike many other lilacs. It exhibits resilience across USDA Hardiness Zones 3 through 8, making it adaptable to a wide range of climates.
Planting Blue Skies Lilac
Planting ‘Blue Skies’ Lilac begins with careful site selection. This shrub thrives in full sun, requiring at least six hours of direct sunlight daily to ensure optimal flower production. Good air circulation around the plant is also beneficial, helping to prevent common issues like powdery mildew. The plant prefers fertile, humus-rich, well-drained soils that are neutral to slightly alkaline, with a pH around 7.0. It performs well in chalky soils but dislikes acidic conditions.
When preparing the planting site, dig a hole that is at least twice the diameter of the root ball and slightly deeper. Loosen the soil around the planting area to encourage root expansion. Place the lilac in the hole at the same depth it grew in its nursery container, ensuring the roots are spread out. Backfill the hole with a mixture of compost and the original soil, then gently tamp down to remove any air pockets. Water the newly planted lilac thoroughly.
The optimal time for planting ‘Blue Skies’ Lilac is either in early fall or early spring, as these mild temperatures allow the roots to establish before extreme weather conditions. Proper spacing, typically 5 to 8 feet apart, should be considered to accommodate the mature width of the shrub.
Ongoing Care and Maintenance
Once established, ‘Blue Skies’ Lilac requires care to maintain vigor and abundant blooms.
Watering
During its first growing season, water consistently and deeply (about one inch per week) for six weeks to develop an extensive root system. After establishment, it becomes more drought-tolerant, but moderate watering every 10 to 14 days is beneficial during prolonged dry periods and the spring blooming season. Avoid overwatering; lilacs do not tolerate soggy conditions, which can harm roots.
Fertilization
Established ‘Blue Skies’ Lilacs generally do not require heavy fertilization, especially after the second year. If soil fertility is low or to promote more blooms, apply a balanced granular fertilizer (e.g., 10-10-10 NPK) in early spring as new growth emerges. A higher phosphorus content can enhance flowering. Avoid over-fertilizing, especially with high-nitrogen formulas, as this promotes foliage growth over flowers.
Pruning
Prune immediately after flowering in late spring or early summer. Pruning later risks removing next year’s flower buds, which form on old wood.
Annual maintenance pruning involves:
Removing any dead, diseased, or broken branches.
Thinning out crossing or rubbing stems to improve air circulation.
Deadheading spent flower panicles to redirect energy from seed production toward developing more flower buds.
Promptly removing root suckers that emerge from the base to maintain appearance and prevent unwanted spread.
For older, overgrown shrubs, perform rejuvenation pruning by removing about one-third of the oldest, thickest stems (those larger than two inches in diameter) each year over a three-year period, cutting them back to the ground. This encourages fresh, more vigorous growth and blooming.