Clustered bellflower

Questions about clustered bellflower

Does clustered bellflower need sun or shade?

Clustered bellflower grows in full sun (6 or more hours of direct sun a day) and part sun (4 to 6 hours of sun, including some afternoon sun).

It wants soil that stays evenly moist, of average fertility, and a good soak in dry spells.

What zones does clustered bellflower grow in?

USDA zones 3 to 8. It is hardy to zone 3, which means it survives winter nights down to about −30 °F (−34 °C).

Above zone 8 it struggles: the zones measure winter cold, but a plant's top zone usually means the summers are too hot or the winters too mild for it to rest.

Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.

When does clustered bellflower flower in my zone?

In zone 5 it flowers early June to early July. As a summer flower it moves about half a week for every zone: earlier where it is warmer.

Worked out from Hopkins' bioclimatic law: spring arrives about four days later for each degree of latitude north, and one zone is roughly two degrees. A warm spring or a cold one moves any garden two weeks either way.

How far apart should clustered bellflower be planted?

16 in (40 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 18 in (45 cm), so a group knits into one patch.

It grows 18 in (45 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.

How many clustered bellflower plants do I need?

At 16 in apart, set out in staggered rows:

• 7 to fill 10 square feet (about 1 m²)
• 8 for a single row 10 ft (3 m) long
• 21 to fill a 4 × 8 ft bed on its own

In a mixed border, plant it as a group of three or five, with a second group further along in the other number.

In the bed above, the planner used three in one group.

Is clustered bellflower poisonous to dogs and cats?

No toxicity is recorded for dogs, cats, horses or people, according to NC State Extension.

"Not toxic" is not "edible": a pet that eats a lot of any plant can be sick.

Is there a native plant like clustered bellflower?

Clustered bellflower comes from Europe and temperate Asia. These North American natives come closest to doing its job:

• Sundrops 'Fireworks': the same job in a bed, the same size and the same flowering time; yellow, not purple, wants average soil.
• Stokes' aster: the same job in a bed, the same size and the same colour; flowers late June to mid August, wants average soil.

Matched the way the planner's Swap button matches plants: the same job in a bed, then size, then flowering time.

Do deer eat clustered bellflower?

Mostly not. NC State lists it as resistant to deer and rabbits. No plant is proof against a hungry deer in a hard winter, but this one is low on the menu.

Will clustered bellflower spread?

It spreads sideways, by runners or roots; the risk of it taking over is moderate. Spreads by underground runners and can crowd its neighbours. Dig out the edges or divide every 2 to 3 years.

What flowers after clustered bellflower?

Clustered bellflower is over by early July. These start as it finishes and carry the same spot on, so it never goes flat:

• Daylily: from late June to early August, 2½ ft tall (a recorded partner).
• Black-eyed Susan: from mid July to mid September, 24 in tall.
• Butterfly weed: from late June to early August, 24 in tall.

What does clustered bellflower look like in winter?

Clustered bellflower dies down, but leave the stems standing: the seed heads stand through the winter, and songbirds eat the seed. Cut them down in early spring, before the new shoots come.

Is clustered bellflower good for bees and butterflies?

Clustered bellflower is visited by pollinators, bees, specialist bees, butterflies, hummingbirds and songbirds.