Blue-stemmed goldenrod

Questions about blue-stemmed goldenrod

Does blue-stemmed goldenrod need sun or shade?

Blue-stemmed goldenrod grows in part sun (4 to 6 hours of sun, including some afternoon sun), part shade (2 to 4 hours of sun, mostly in the morning) and shade (less than 2 hours of direct sun, or bright dappled light).

It wants ordinary well-drained soil, of average fertility, and little watering once settled. Once settled in, it stands drought.

What zones does blue-stemmed goldenrod grow in?

USDA zones 4 to 8. It is hardy to zone 4, which means it survives winter nights down to about −20 °F (−29 °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 blue-stemmed goldenrod flower in my zone?

In zone 5 it flowers early September to mid October. As an autumn flower it keeps much the same dates in every zone: it answers to shortening days and cool nights more than to the warmth of spring.

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 blue-stemmed goldenrod be planted?

18 in (45 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 24 in (60 cm), so a group knits into one patch.

It grows 2½ ft (75 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.

How many blue-stemmed goldenrod plants do I need?

At 18 in apart, set out in staggered rows:

• 5 to fill 10 square feet (about 1 m²)
• 7 for a single row 10 ft (3 m) long
• 17 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 one in one group.

Is blue-stemmed goldenrod 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.

Do deer eat blue-stemmed goldenrod?

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

What flowers after blue-stemmed goldenrod?

Blue-stemmed goldenrod is over by mid October. These start as it finishes and carry the same spot on, so it never goes flat:

• Japanese onion 'Ozawa': from early October to early November, 10 in tall, to stand in front of it and cover its fading stems.
• Bodnant viburnum 'Dawn': from early November to late December, 10 ft tall.
• Common witch hazel: from mid October to late November, 15 ft tall.

What does blue-stemmed goldenrod look like in winter?

Blue-stemmed goldenrod 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 blue-stemmed goldenrod good for bees and butterflies?

Blue-stemmed goldenrod is visited by pollinators, specialist bees, butterflies and songbirds.

It is a host plant: the caterpillars of wavy-lined emerald feed on its leaves. A butterfly can only lay its eggs on its host plants, so these do more for it than any nectar flower.

It is native to the United States and Canada.