Calibrachoa

A miniature petunia relative with masses of small, bell-shaped flowers that cascade beautifully from containers and baskets. Calibrachoa is self-cleaning and blooms prolifically without deadheading in a wide array of colors. Use acidic potting mix and iron-containing fertilizer to prevent yellowing foliage.

Nearly all calibrachoa sold commercially are patented hybrid varieties propagated from cuttings, not seed. The few seed-available varieties, such as the Kabloom series, should be started indoors ten to twelve weeks before the last frost. Sow tiny pelleted seeds on the surface of moist acidic seed-starting mix without covering. Seeds germinate in ten to fourteen days at 70 to 75 degrees Fahrenheit with consistent moisture. Most gardeners find it more practical to purchase established transplants each spring.

The Season Plate

Your Calibrachoa Year

Composed for Zone 7 · typical seasons · frost passes Apr 2, returns Nov 1

Sow Calibrachoa Apr – May, pick May – Oct. Set your climate below and every date on this plate re-times itself.

Sowing window

Apr – May

re-timed to your frost dates

Plant out

after Apr 2

once frost risk has passed

First picking

around Jun 4

≈ 50 days from sowing · 300 to per plant

Composed for —ColdTemperateMildWarmUse my locationUsed once to set your season · only the zone is kept

Week-by-week Calibrachoa reminders watering, feeding and pruning, timed to your dates

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Frost alerts for your garden a warning before a cold night costs you the crop

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Succession sowing dates so the picking never gaps mid-season

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Calibrachoa is almost exclusively purchased as nursery transplants, as the hybrid varieties do not come true from seed and are vegetatively propagated. Plant outdoors after all danger of frost in full sun, spacing eight to twelve inches apart. Calibrachoa is outstanding in hanging baskets, window boxes, and containers where its trailing habit can cascade over edges.

Use acidic potting mix with a pH of 5.5 to 6.0, as calibrachoa is highly susceptible to iron chlorosis in alkaline conditions. Mix in peat moss or use an azalea-camellia potting blend. Water regularly, keeping soil consistently moist but never waterlogged. Container plants in hot weather may need daily watering. Ensure containers have excellent drainage.

Feed every one to two weeks with an acidic liquid fertilizer containing iron and other micronutrients. Calibrachoa is a heavy feeder and will decline without regular nutrition. The plants are self-cleaning and rarely need deadheading. If stems become leggy in midsummer, trim back by one-third to encourage fresh bushy growth. Calibrachoa blooms continuously from spring through frost with proper care, producing hundreds of small petunia-like flowers over the season.

Calibrachoa is a superb container companion, cascading over basket edges while upright plants like geraniums, salvia, or angelonia provide height. Combine with trailing sweet potato vine and verbena for a lush, overflowing basket. Pair with petunias, though note that calibrachoa often outperforms petunias in rainy weather. The small flowers complement the bolder blooms of larger companions without competing. Use multiple calibrachoa colors together for a confetti-like explosion of color.

The Society Table

Petunia belongs beside it.

Old growers' knowledge, checked against Calibrachoa's real companion table below — test any plant you're growing.

Grows well in the company of · 3

PetuniaVerbenaLobelia

Keep apart · 0

no recorded foes

Plant Calibrachoa with good neighboursThe planner flags conflicts before they're in the ground

Related growing guides

Flowers

Petunia

A good companion for Calibrachoa

Flowers

Verbena

A good companion for Calibrachoa

Flowers

Lobelia

A good companion for Calibrachoa

Flowers

Sunflower

View growing guide

Calibrachoa demands acidic, well-drained potting mix with a pH of 5.5 to 6.0. Use peat-based potting mixes or azalea-camellia blends. Iron chlorosis is the single biggest nutritional issue, caused by alkaline soil or water. Feed every one to two weeks with an acidic liquid fertilizer that includes iron, manganese, and other micronutrients. Slow-release granular fertilizer can be mixed into potting soil at planting. Never allow containers to sit in standing water.

Ideal Temperature

Hardiness Zone Compatibility

Calibrachoa flowers are too small for traditional cutting, but trailing stems can be snipped and used in small bud vases or as filler in miniature arrangements. The plants are best enjoyed in their containers and baskets. Deadheading is unnecessary as calibrachoa is self-cleaning. If plants become leggy or bloom production slows in midsummer, trim all stems back by one-third to stimulate a fresh flush of flowers within two to three weeks. Take stem cuttings in late summer to root for overwintering.

Storage & Preservation

Calibrachoa is not suitable for cut flowers or drying. To preserve favorite varieties over winter, take three to four inch stem cuttings in late summer. Root them in moist perlite or vermiculite under high humidity, then pot up and grow in a bright, cool window through winter. Alternatively, bring entire containers indoors before frost and maintain in a sunny location at 55 to 65 degrees. Reduce watering during winter. Move plants back outdoors after the last spring frost.

Iron Chlorosis

Disease

Yellowing between leaf veins while veins remain green, starting on youngest leaves. Severe cases cause bleached white foliage and stunted growth.

Prevention Use acidic potting mix with pH below 6.0. Apply iron-containing fertilizer regularly. Avoid alkaline water sources.

Fix: Apply chelated iron as a foliar spray or soil drench for quick greening. Acidify potting mix with sulfur. Switch to an acidic fertilizer formula.

Aphids

Pest

Small clusters of insects on tender shoot tips and flower buds, sticky honeydew on leaves below, distorted new growth.

Prevention Inspect plants regularly. Avoid excessive nitrogen fertilization. Encourage beneficial insects in the garden.

Fix: Spray with a forceful water jet. Apply insecticidal soap or neem oil. Systemic insecticides provide longer-term control for severe infestations.

Tobacco Mosaic Virus

Disease

Mottled yellow and green patterns on leaves, distorted growth, stunted plants, and reduced flowering.

Prevention Purchase plants from reputable sources. Wash hands and sterilize tools between handling different plants. Remove infected plants immediately.

Fix: No cure exists. Remove and destroy infected plants. Disinfect containers and tools with a ten percent bleach solution before replanting.

Black Root Rot

Disease

Stunted growth, yellowing foliage, dark brown to black roots when inspected. Plants decline gradually despite proper watering.

Prevention Use sterile potting mix. Maintain acidic soil pH. Avoid overwatering and ensure excellent drainage. Purchase disease-free plants.

Fix: Remove and discard infected plants and contaminated potting mix. Disinfect containers. Replant with fresh, sterile mix and healthy plants.

Troubleshooting Common Problems

Iron chlorosis from alkaline soil or water is by far the most common problem, causing yellowing leaves and plant decline. Test water pH and use acidic fertilizer. Overwatering and poor drainage cause root rot, especially in containers without drainage holes. Tobacco mosaic virus can devastate calibrachoa. Avoid handling plants after touching tobacco products. In very hot weather, plants may benefit from afternoon shade. Leggy growth mid-season is easily corrected by trimming back.

Growing Tips

1. Always use a well-draining soilless potting mix with at least 20 percent perlite; calibrachoa roots rot quickly in heavy or waterlogged soil.
2. Maintain soil pH between 5.5 and 6.0 for optimal nutrient uptake; if leaves turn yellow with green veins, apply chelated iron and acidify the soil with an aluminum sulfate drench.
3. Water thoroughly until it drains from the bottom, then allow the top centimeter of soil to dry before watering again; calibrachoa prefers an even moisture cycle rather than constant wetness.
4. Feed every 7 to 10 days with a water-soluble fertilizer during active growth; alternate between a balanced formula and a high-phosphorus bloom booster for the best results.
5. Provide at least 6 hours of direct sunlight daily; calibrachoa blooms most prolifically in full sun but appreciates afternoon shade in regions with temperatures above 35°C.
6. Cut back leggy stems by one-third in midsummer if flowering slows; this hard pruning stimulates a vigorous flush of new growth and blooms within 10 to 14 days.
7. Monitor for tobacco budworm, the most damaging pest of calibrachoa; look for small holes bored into flower buds and treat with Bacillus thuringiensis (Bt) spray in the evening.
8. Avoid overhead watering, which promotes fungal diseases like black root rot and powdery mildew; use a watering can or drip system directed at the soil surface.
9. Rotate fertilizer types monthly to prevent salt buildup in containers; flush pots with plain water every 4 weeks to leach accumulated salts from the potting mix.
10. When planting mixed containers, pair calibrachoa with plants that share its preference for acidic soil and good drainage, such as verbena, nemesia, lobelia, and sweet potato vine.