PL. —Solanum pyracanthumBotanical illustration — drop image
Solanum pyracanthum

Porcupine Tomato

SummerFallInvasive
9b11bHardiness zone
Peak bloom windowZone 6b · frost-offset weeks
Winter
Not in bloom
Spring
Peak bloom
Summer
Peak bloom
Fall
Not in bloom
Peak bloom
In bloom
Background

Solanum pyracanthum is a tropical evergreen shrub from Madagascar grown for its vivid orange prickles along stems and leaf midribs, silver-gray felted foliage, and small violet-purple flowers typical of the Solanum genus. A single specimen delivers strong visual impact as a focal point or dramatic accent in a warm-climate garden.

In zones 9b–11b it grows as a woody perennial. In cooler climates it is treated as a tender annual or maintained in containers overwintered indoors in a frost-free, bright location. It performs best in hot, sunny positions with excellent drainage and is drought-tolerant once established. Good air circulation in humid climates reduces fungal disease pressure. Soil pH near neutral is adequate; no fertilization beyond a light annual top-dress is needed.

The rigid, densely spaced orange prickles make it effective as a barrier planting along property edges or beneath windows where physical deterrence is a design priority.

Care guide
SunFull sun
WaterLow to moderate; drought tolerant once established
SoilLean, well-drained
Spacing24–36 inches
Height2–4 ft
Zone9b – 11b
Invasive
Seasonal tasks
winter
sowStart seeds indoors in moist seed-starting mix at 70–80°F. Germination typically takes 2–4 weeks at consistent warmth.
spring
cutPrune lightly to shape and remove dead or crossing stems. Use heavy leather gloves and long-handled tools — prickles penetrate ordinary garden gloves.
sowTransplant seedlings outdoors into full sun after all frost danger has passed and nighttime temperatures remain reliably above 55°F.
summer
watchMonitor for spider mites and whitefly during hot, dry spells. Treat early with insecticidal soap or a strong water spray directed at leaf undersides.
watchCheck foliage for powdery mildew and fungal leaf spot in humid conditions. Improve air circulation and remove affected leaves promptly.
watchWatch for yellowing or wilting stems, which may indicate verticillium or fusarium wilt, especially where drainage is poor or soil has hosted other Solanaceae.
fall
cutIn zone 9b or marginal areas, cut back by one-third and move container plants to a frost-free, bright indoor location before first frost.
Common problems

Fusarium wilt

Symptoms

Sudden wilting, brown streaks in stems, yellowing leaves. Affects sweet basil varieties most.

Treatment

No cure. Remove and destroy plants. Do not replant in the same spot for 3+ years. Choose resistant varieties.

Verticillium Wilt

Symptoms

Lower leaves yellow and wilt, often on one side of the plant, with brown streaking in the stem and crown tissue when cut open. Plants are stunted and decline over the season.

Treatment

Remove and destroy affected plants. Avoid planting in soil that has grown infected tomatoes, peppers, or other susceptible crops. Rotate beds and improve drainage; there is no cure once a plant is infected.

Root rot

Symptoms

Plants wilt, yellow, and stunt even in moist soil; lower stems and roots turn brown, soft, and mushy and the plant may collapse. Most common in heavy, wet, or poorly drained ground.

Treatment

Improve drainage and stop overwatering, and never plant too deep. Lift and destroy badly affected plants along with the soil around the roots. Grow in raised or free-draining beds to prevent it returning.

Powdery mildew

Symptoms

White or grey powdery coating on leaves — usually starting on older growth in humid conditions or when nights cool.

Treatment

Improve air circulation by thinning plants. Apply neem oil or potassium bicarbonate spray at first sign. Avoid overhead watering.

Fungal leaf spot

Symptoms

Brown or purplish spots on the leaves, often ringed with a yellow halo, that spread and merge in warm, humid, or wet weather; heavily spotted leaves yellow and drop early.

Treatment

Pick off spotted leaves and clear fallen debris to remove overwintering spores. Improve air circulation by thinning, and water at the base so foliage dries quickly. If it persists, apply a copper- or sulfur-based fungicide at the first sign.