Propagate by division or separation - Divide at least every 2 years to maintain health. Space to allow for good air circulation when replanting.

May self-seed. Hybrids may not breed true.

Tall varieties are more likely to require staking. Pinching or cutting them back several times before late July will reduce their height, increase bushiness, delay flowering, produce more flowers and reduce staking needs.

To reduce foliage diseases, thin stems so they are about 1 inch apart. Cutting the outer stems lower than those to the inside of the plant encourages a fuller, more rounded shape.

Deadhead or cut plants to the ground after flowering to prevent self-seeding. Self-seeded plants aren't true to parental type.

Divide every 1 to 2 years in spring.

More growing information: How to Grow Perennials

Rosy blister gall
Aphids
Tarsonemid mites
Nematodes
Slugs and snails

Verticillium wilt
Gray mold
Powdery mildew
Rust
White smut
Aster yellows
Leaf spots
Stem cankers

These varieties are all more than 2 feet tall. See separate listing for short varieties.

‘Ada Ballard’ grows 3 feet tall and has violet-blue blooms.

‘Bonningale White’ grows 3.5 feet tall and has double white blooms.

‘Coombe Margaret’ grows 3.5 feet tall and has semi-double rosy pink blooms.

‘Crimson Brocade’ grows 3 feet tall and has semidouble deep red blooms.

‘Eventide’ grows 3 feet tall and has semidouble purple blooms.

‘Marie Ballard’ grows 2.5 feet tall and has double pale blue blooms.

‘Patricia Ballard’ grows 2.5 feet tall and has double, deep pink blooms.

‘White Lady’ grows 5 to 6 feet tall and has white blooms with orange-yellow centers.

‘Winston Churchill’ grows 2.5 feet tall and has vivid red blooms.