Ornamental · Balsaminaceae
Impatiens
Impatiens walleriana
Give it shade and steady moisture, and impatiens floods a shady bed with color all summer.
Partial shade
59–75°F · 15–24°C
60–90 days
USDA 10–11
Overview
Few plants bring color to a shady spot the way impatiens does. This tender perennial from East Africa is grown almost everywhere as a warm season annual, filling beds, borders, and pots with bloom from late spring until the first frost. Where most flowers sulk without sun, it thrives in the partial to full shade under trees and on the north side of a house.
It earned the old nickname Busy Lizzie for good reason, flowering steadily without much fuss and asking little beyond moist soil and a break from the hot afternoon sun. The plants stay low and mounded, between 6 and 24 inches (15 to 61 cm) tall, and spread about as wide, so a few quickly knit into a sheet of color.
One shadow hangs over the classic seed impatiens: a disease called downy mildew that swept through gardens and made the old favorites a gamble. The fix is to reach for newer resistant varieties, which is why names like Beacon matter when you're choosing what to plant.
Care
The short version: plant impatiens in partial to full shade, keep the soil evenly moist, feed monthly, and pull off spent blooms to keep the flowers coming.
Light
Impatiens are shade plants through and through, happiest in partial to full shade where they bloom without burning. Hot, direct sun scorches the leaves and leaves the whole plant wilting, so give it the dappled light under trees or a north-facing spot.
Water
Keep the soil consistently moist, since impatiens wilt fast the moment they dry out, though they usually bounce back if you water them promptly. Water at the base rather than over the top, because wet foliage invites downy mildew and gray mold. In heavy, poorly drained soil, hold back, as soggy roots rot.
Soil
Plant in fertile, organically rich ground that holds moisture yet drains freely. Working in compost gives the roots the steady, even dampness these plants depend on.
Temperature
Impatiens like it mild, between 59°F and 75°F (15°C to 24°C). They are tender and frost finishes them off, so wait for warm settled weather before setting plants outside.
Humidity
Ordinary outdoor humidity suits them fine, so there's no number to chase. Airflow is what matters, since crowded, stagnant plantings hold the damp that downy mildew and gray mold need to take hold.
Feeding
Feed monthly through the growing season with a balanced fertilizer, or a weaker liquid feed more often, and remember that plants in pots get hungry faster. Go easy on the nitrogen, which pushes soft growth that aphids love.
Pruning
Deadhead the spent flowers to keep new buds coming, and clip away any damaged or diseased growth as you spot it. That little bit of tidying keeps the plant blooming and the air moving.
Size & spacing
Plants reach 6 to 24 inches (15 to 61 cm) tall and spread about the same. Give each one room to fill out so air can move between them, which keeps disease at bay.
When to plant
Impatiens hate frost and won't go out until the cold has truly passed. Start seed indoors in late winter, set the plants out once the last frost is behind you and the soil has warmed, and enjoy bloom from late spring to the first fall frost.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: 8 to 10 weeks before the last spring frost
- Plant: After the last spring frost once soil has warmed
- Harvest: Late spring to the first fall frost
Hardiness
USDA hardiness zones: 10–11
Temperature: down to -1°C
Troubleshooting
Most impatiens trouble shows up on the leaves first, whether from disease in damp weather or pests in dry heat. Catch the signs early and you can act before a small problem takes the whole planting. Match what you see below, then step in while it still helps.
Yellowing, curling leaves and a plant that drops to bare stems
This is impatiens downy mildew, the disease that wiped out bedding impatiens across much of the country. Leaves yellow and curl down, a white fuzz coats their undersides, and within days the plant sheds its foliage and stands as bare stems. There is no saving an infected plant, so pull it, bag it, and never compost it.
Fix:
- Remove and bag infected plants including fallen leaves and do not compost them
- Note that fungicides cannot cure infected plants and only protectant fungicides slow spread
- Replant with resistant types such as Beacon or Imara XDR, New Guinea impatiens or SunPatiens, or switch to begonia, coleus, or caladium
Stippled, bronzed leaves with faint webbing in hot weather
Fine speckling and a bronze cast on the leaves point to spider mites, which thrive when the air turns hot and dry. Tap a leaf over white paper and you'll see the specks crawl. Rinse the foliage, raise the humidity around the plant, and treat with insecticidal soap or horticultural oil on the schedule the label gives.
Fix:
- Rinse foliage and raise humidity
- Apply insecticidal soap or horticultural oil, repeating as directed
Fuzzy gray mold on faded flowers in damp weather
Botrytis blight, also called gray mold, settles on spent flowers and soft tissue when the weather stays cool and damp. A light gray, cobweb-like fuzz spreads from dying blooms onto leaves and stems. Pick off the faded flowers and rotted parts, open the planting up for better airflow, and keep water off the foliage.
Fix:
- Remove spent flowers and affected tissue
- Improve air circulation and avoid wetting foliage
Sticky new growth crowded with tiny insects
Those clusters on the soft new shoots are aphids, and the sticky film they leave behind is honeydew. They twist the young leaves but rarely do lasting harm. Blast them off with a sharp jet of water, then follow up with insecticidal soap or horticultural oil if they keep coming back.
Fix:
- Dislodge them with a strong jet of water
- Apply insecticidal soap or horticultural oil as needed
Toxicity
Good news for pet owners and parents: impatiens is safe. The ASPCA lists it as non-toxic to cats, dogs, and horses, and it poses no poisoning risk to the other common household animals or to people. You can plant it where pets graze and children play without worry.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Safe to have around cats. A curious nibble on the leaves or flowers won't poison them.
Dogs None
No toxins here, so dogs are fine near it. A dog that chews a stem might get a mild, passing stomach upset, as with any plant.
Horses None
Listed as non-toxic to horses, so a grazing horse has nothing to fear from it.
Rabbits Safe
Rabbits can browse the foliage without harm. Some keepers even grow impatiens as a safe nibble.
Livestock Safe
Goats, sheep, and cattle face no poisoning risk from it.
Birds Safe
Pet and backyard birds are fine around the plant and its flowers.
People Safe
Not poisonous to people, and the flowers are sometimes eaten as a garnish. Still, plants are not a food crop, so don't make a meal of it.
Varieties
Hundreds of impatiens have come and gone, but a few names are worth knowing, above all the ones bred to stand up to downy mildew.
Super Elfin
An early, compact seed series in a wide color range, though like most older Impatiens walleriana it falls hard to downy mildew.
Beacon
Bred for strong resistance to impatiens downy mildew, so seed impatiens can grow again in gardens where the disease has settled in.
Double-flowered (rosebud) types
These carry full, rose-like double blooms instead of the usual flat, five-petaled single flowers.
How to propagate
Impatiens are easy to multiply, whether you start a packet of seed indoors in late winter or take quick cuttings from a plant you already love.
SeedModerate
Sow indoors 8 to 10 weeks before the last spring frost · Germinates in about 1 to 3 weeks; flowers roughly 10 to 13 weeks after sowing
Start seed indoors about 8 to 10 weeks before your last spring frost. Press the seed onto the surface and leave it uncovered, since impatiens need light to sprout, and keep the mix warm at around 75°F (24°C) and humid. Seedlings break ground in 1 to 3 weeks and reach bloom roughly 10 to 13 weeks after sowing.
Stem cuttingsEasy
Spring through summer · Roots in about 1 to 2 weeks
Tip cuttings taken from spring through summer root with almost no fuss, striking in 1 to 2 weeks in a glass of water or a pot of moist mix. This is the reliable way to carry a favorite plant through winter indoors. Take cuttings only from healthy stock that shows no sign of downy mildew.
Myths
Impatiens need full sun to bloom well.
It's the other way around. Impatiens walleriana is a shade plant that flowers best in partial to full shade, and hot, direct sun scorches the leaves and leaves it wilting.
Fungicides will cure impatiens that already have downy mildew.
A fungicide only shields plants that are still healthy and cannot cure one already infected, which needs to come out. Your better move is to replant with resistant varieties.