Common Name: Jacob's ladder
Type: Herbaceous perennial
Family: Polemoniaceae
Zone: 4 to 8
Height: 3.00 to 3.50 feet
Spread: 1.00 to 2.00 feet
Bloom Time: April to May
Bloom Description: Cobalt blue
Sun: Part shade to full shade
Water: Medium
Maintenance: Medium
Flower: Showy, Fragrant
Tolerate: Deer, Heavy Shade
Culture
Grow in average, medium moisture, well-drained soils in part shade to full shade. Best leaf color may occur in part shade. Prefers rich, humusy, consistently moist soils. Soils must not be allowed to dry out. Best performance occurs in cool summer climates. Plants are intolerant of the high heat and humidity of summers in the deep South. Plants may be cut back to basal foliage after bloom or if foliage declines to tidy the planting and to encourage a possible late summer rebloom.
Noteworthy Characteristics
Polemonium is a genus of about 25 species of herbaceous perennials from Europe, Asia, North and Central America. They are grown for their showy flowers.
Genus name comes from the Greek name polemonion originally applied to a medicinal plant associated with Polemon of Cappadocia.
‘Lace Towers’ is a Jacob’s ladder cultivar that grows in an erect clump to 3.5’ tall. It features odd-pinnate compound bright green leaves (to 27 leaflets each) that appear ladder-like, hence the common name. Cup-shaped, cobalt blue flowers appear in loose, terminal clusters (cymes) in spring (April-May in the St. Louis area). Flowers are fragrant.
Problems
Leaf spot and powdery mildew can be problems, particularly in humid climates. Foliage may scorch in too much sun. Leaflet tips will brown up if soils are allowed to dry out. Foliage will generally decline and become less attractive as the summer progresses. Watch for slugs.
Uses
The flowers will brighten shady locations in borders, woodland gardens, cottage gardens or shade gardens.