Cup plant

Questions about cup plant

Does cup plant need sun or shade?

Cup plant grows in full sun (6 or more hours of direct sun a day).

It wants soil that stays evenly moist, rich in organic matter, and a good soak in dry spells. Once settled in, it stands drought.

What zones does cup plant grow in?

USDA zones 3 to 9. It is hardy to zone 3, which means it survives winter nights down to about −30 °F (−34 °C).

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

When does cup plant flower in my zone?

In zone 5 it flowers mid July to early September. 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 cup plant be planted?

3 ft (90 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 3½ ft (100 cm), so a group knits into one patch.

It grows 8 ft (240 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.

How many cup plant plants do I need?

At 3 ft apart, set out in staggered rows:

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

In a mixed border, plant it as one, with clear ground around it: a feature plant is seen as an object, and a group of them is a thicket.

Is cup plant 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.

What can I plant instead of cup plant?

Cup plant is listed as invasive in parts of North America, so the planner never uses it. These do the most similar job, and are native:

• Sweet Joe Pye weed: the same job in a bed and the same flowering time; 24 in shorter, pink, not yellow.
• Hardy hibiscus: the same job in a bed and the same flowering time; 3 ft shorter, red, pink or white, not yellow.

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

Do deer eat cup plant?

They may. NC State does not list it as resistant to deer or rabbits. Where they visit, protect it, or plant it among ones they avoid.

Will cup plant spread?

It seeds itself about; the risk of it taking over is high. Self-seeds heavily and forms large colonies. Native to the central United States, but listed as invasive in parts of the Northeast and banned from sale in New York and Connecticut. Check local guidance before planting.

It is listed as invasive in parts of North America, and the planner never chooses it.

What flowers after cup plant?

Cup plant is over by early September. These start as it finishes and carry the same spot on, so it never goes flat:

• New England aster: from early September to mid October, 4 ft tall, to stand in front of it and cover its fading stems (a recorded partner).
• Garden chrysanthemum: from mid September to late October, 24 in tall, to stand in front of it and cover its fading stems.
• Swamp sunflower: from late September to late October, 6½ ft tall.

What does cup plant look like in winter?

Cup plant 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 cup plant good for bees and butterflies?

Cup plant is visited by pollinators, bees, butterflies, hummingbirds, beneficial insects and songbirds.

It is native to the United States.