Alcea rosea 'Blacknight'
Blacknight Hollyhock flowers
(Photo courtesy of NetPS Plant Finder)
Plant Height: 4 feet
Flower Height: 6 feet
Spread: 24 inches
Hardiness Zone: 3a
Other Names: Althaea rosea
Group/Class: Spotlight™ Series
Brand: Walter's Gardens
Featuring deep black-purple flowers on towering spikes in midsummer; this biennial is tolerant to the natural toxin formed by the roots of Black Walnut; selections from this series are truly perennial; plant in full sun for better growth
Blacknight Hollyhock features bold spikes of black round flowers with white eyes and deep purple streaks rising above the foliage from mid to late summer. The flowers are excellent for cutting. Its large tomentose round leaves remain grayish green in colour throughout the season. The fruit is not ornamentally significant.
Blacknight Hollyhock is an herbaceous perennial with a rigidly upright and towering form. Its relatively coarse texture can be used to stand it apart from other garden plants with finer foliage.
This is a high maintenance plant that will require regular care and upkeep, and should only be pruned after flowering to avoid removing any of the current season's flowers. It is a good choice for attracting hummingbirds to your yard, but is not particularly attractive to deer who tend to leave it alone in favor of tastier treats. Gardeners should be aware of the following characteristic(s) that may warrant special consideration;
Blacknight Hollyhock is recommended for the following landscape applications;
- Vertical Accent
- Mass Planting
- General Garden Use
Planting & Growing
Blacknight Hollyhock will grow to be about 4 feet tall at maturity extending to 6 feet tall with the flowers, with a spread of 24 inches. It tends to be leggy, with a typical clearance of 1 foot from the ground, and should be underplanted with lower-growing perennials. The flower stalks can be weak and so it may require staking in exposed sites or excessively rich soils. It grows at a fast rate, and under ideal conditions can be expected to live for approximately 10 years.
This plant should only be grown in full sunlight. It prefers to grow in average to moist conditions, and shouldn't be allowed to dry out. It is not particular as to soil type or pH. It is highly tolerant of urban pollution and will even thrive in inner city environments. This is a selected variety of a species not originally from North America.