Garden flowers come in an almost endless variety, from tiny, low-growing groundcovers to tall spikes of blooms. Very tall flowers make an attractive backdrop for smaller plants in garden beds, along walls and along privacy hedges. A number of flower varieties that will get very tall can add height and drama to your garden area.
Everyone recognises sunflowers. These cheerful blooms add a distinctive look to any garden. Some cultivars can grow to 12 feet tall, so it's important to make sure they will have sufficient headroom if you are planting close to garden structures. Sunflowers come in both annual and perennial varieties and are hardy to Zone 4, according to Prairie Nursery, a Wisconsin commercial producer of native seeds and flowers.
Tall penstemon superbus, also called "superb beardtongue," bears spectacular, coral flowers on long clusters of stems that grow 6 feet tall. It has grey-green leaves and prefers full sun or partial shade. Penstemon superbus is a short-lived perennial that blooms in February and can continue under certain conditions to June. This plant is hardy to Zone 7, according to Integrated Landscape Management.
Cosmos is a garden favourite, but many people don't know about the varieties that grow very tall. Cosmos Sensation grows to 3 feet tall and can be sowed directly outdoors as soon as all danger of frost has passed. According to Millington Seeds, Cosmos Sensation blooms 10 weeks after planting with white, pink, rose or crimson flowers. Cosmos are annual plants that are hardy from Zones 7 to 10.
Delphinium Centurion grows 4-to-5-foot spires of colourful blooms in blue, white and rose. Start plants indoors and they will provide first-year flowers. The double flowers provide spectacular colour in mass plantings. They grow best in full sun, but also grow in partial shade in warm climates, according to Park Seeds. Delphinium is a perennial plant that is hardy from Zone 3 to Zone 7.
Hollyhocks come in many cultivars of varying heights. The Antwerp hollyhock grow to 6 to 9 feet tall. It is hardy to Zone 4 and bears 3-to-6-inch blooms. Sow the seeds indoors in trays of sandy soil and keep them moist. Transplant the plants to outdoor beds filled with loamy soil after all danger of frost has passed. Remove spent flowers from the plants to encourage more blooms. Hollyhocks are perennial plants that are hardy from Zone 3 to Zone 9.
Cannas are bulb plants that are available in a variety of cultivars and colours. They grow in tropical and subtropical regions, so plan to dig them up and store them over winter if you live in a cold climate. Some varieties can grow to 8 feet tall. Giant cannas are hardy from Zone 7 to Zone 11.