summer poinsettia (Amaranthus tricolor) - How to Grow & Care Guide

Plant Snapshot

Common Name: summer poinsettia
Latin Name: Amaranthus tricolor
Alternate Names: Josephs coat, tricolor amaranth, edible amaranth
Hardiness Zones: Tender annual. Frost sensitive so usually grown as an annual outside frost free areas. In frost free regions plants may persist year round.
Typical Height: 1–4 ft (30–120 cm).
Typical Spread: 1–2 ft (30–60 cm).
Bloom Period: Summer to fall until frost.
Soil Preferences: Fertile, well drained soil. Tolerates average to poorer soils if not waterlogged. Prefers slightly acidic to neutral pH around 6.0–7.5. Poor drainage leads to root decline and reduced vigor.
Light Preferences: Full sun for best foliage color. Tolerates light afternoon shade but will be leggier and less colorful in shade.
Toxicity: Leaves are used as a cooked leafy vegetable in many regions but plant tissues contain oxalates and can accumulate nitrates. Some Amaranthus species have been associated with livestock nitrate or oxalate poisoning. May cause mild gastrointestinal upset if eaten by pets.
Propagation: Propagate by seed. Sow outdoors after last frost or start indoors and transplant. Plants may self seed in warm climates.

Key Facts

Tender annual grown for bold, variegated foliage.
Commonly called summer poinsettia or Josephs coat.
Leaves show combinations of red, yellow, and green.
Produces upright flower panicles in summer to fall.
Easily grown from seed and suitable for beds and containers.
Prefers full sun for best foliage color.
Tolerant of average soils but needs good drainage.
Leaves are eaten as a cooked vegetable in some cuisines.
May accumulate nitrates or oxalates and can be a livestock risk.

Summer poinsettia is a tender annual grown for bold variegated foliage in shades of red yellow and green. It is easy to grow from seed and shows upright flower panicles in summer to fall while performing best in full sun and well drained soil.

Identification

Summer poinsettia displays bold variegated leaves in combinations of red yellow and green and produces upright flower panicles in summer to fall. Plants form an upright clump typically 1 to 4 ft tall and 1 to 2 ft across depending on cultivar and spacing. Leaves are the main ornamental feature rather than the flowers.

Best uses and where to grow

Use summer poinsettia as a bright bedding plant border accent or container specimen where full sun is available. Color is strongest in sun while plants become leggy and less intense in shade. Because the species is frost sensitive it is usually grown as an annual outside frost free regions but may persist where frost does not occur.

Planting time and propagation

Sow seed outdoors after the last frost or start seed indoors and transplant when seedlings are settled. Seeds germinate readily and plants establish quickly into summer displays. In warm climates plants often self seed so allow or remove mature seed heads depending on whether you want volunteers the next season.

Spacing and containers

Space plants about 12 to 24 inches apart to match their mature spread and allow air circulation. Compact cultivars may be placed closer while taller types need more room. Summer poinsettia does well in containers provided the potting mix drains freely and you use a slightly larger pot to support the top heavy foliage.

Watering and soil

Plant in fertile well drained soil with a pH around 6.0 to 7.5 for best growth while the species tolerates average soils if they do not remain waterlogged. Overwatering and poor drainage cause root decline and reduced vigor. Moderate regular watering keeps foliage fresh while drought stress leads to leaf drop and faded color.

Edible uses and cautions

Leaves are cooked as a leafy vegetable in many cuisines and provide edible greens when prepared. Plant tissues can accumulate nitrates and oxalates under some conditions so check local guidance before feeding to livestock. Pets that eat the plant may have mild gastrointestinal upset so avoid large quantities around animals.

After flowering and winter care

Because summer poinsettia is usually grown as an annual remove plants at season end or cut back after frost. Collect seeds from mature flower panicles for sowing next year. In frost free areas plants may persist year round and can be thinned or pruned to maintain shape and vigor.

Managing spread and reseeding

Control unwanted volunteers by deadheading flower panicles before seeds mature or by removing seedlings while small. Thin dense plantings to improve air flow and reduce disease pressure. If you want a self renewing patch allow some seed heads to mature and limit spreading with regular removal of extra seedlings.

Frequently asked questions

How fast does summer poinsettia grow?: It is a fast growing annual that reaches its mature height in a single season. Exact speed varies with cultivar soil fertility and sunlight.
Is summer poinsettia edible?: Yes leaves are used as a cooked leafy vegetable in many regions. Prepare as local recipes recommend and avoid raw large quantities.
Is summer poinsettia toxic to pets or livestock?: Plant tissues can accumulate nitrates and oxalates and some species have caused livestock issues under certain conditions. Pets may get mild stomach upset if they eat the plant.
Can summer poinsettia overwinter?: It is frost sensitive and typically grown as an annual outside frost free areas. In frost free climates plants may persist year round.
How do I get the best foliage color?: Provide full sun regular feeding and well drained soil. Shade causes legginess and less intense leaf color.