Comfrey (Symphytum officinale)
Comfrey is the kind of plant that earns a permanent place in a food forest once you see what it does to a patch of soil. It rises in thick, leafy clumps with broad, textured leaves and drooping bell-shaped flowers that quietly pull bees into the garden. The real magic is underground: comfrey develops a deep root system that mines minerals and moisture, then turns that into a steady supply of “chop-and-drop” mulch you can cut several times a year.
In Florida planting zone 9, comfrey can be a useful support plant where it gets consistent moisture and a bit of afternoon relief from brutal heat. Place it where you actually want biomass: around fruit trees, near compost areas, or beside paths where you can harvest leaves without stepping into your beds.
Management note: common comfrey can spread by seed and by root fragments. If you want comfrey benefits with less risk of seedlings, many gardeners choose sterile Russian comfrey selections (often sold as “Bocking” types) for long-term control.
Any reference to medicinal or culinary use of plants or plant parts should in no way be considered an endorsement by The Ocala Food Forest or its staff. Research is crucial in safe and proper consumption or experimentational use of any plant.
Plant Information
| Scientific Name: | Symphytum officinale |
|---|---|
| Family Name: | Boraginaceae (Borage family) |
| Common Name(s): | Comfrey, Common Comfrey, Knitbone (historic name) |
| Size: | Typically 2–4 ft tall and 2–3+ ft wide (larger with rich soil and steady moisture) |
| Plant Type: | Perennial herb (clump-forming); regrows rapidly after cutting |
| Origin/Geographic Distribution: | Native to Europe and parts of western Asia; widely cultivated and naturalized elsewhere |
| Native to: | Europe / western Asia (not Florida native) |
| Planted range in the USA: | Grown in gardens across much of the U.S., especially in permaculture and medicinal/herb gardens |
| Conservation Status: | Not listed as threatened or endangered |
| Florida Status: | Non-native; generally used as a managed garden plant (control spread and avoid dumping roots) |
Cultivation
| Planting: | Plant in fall through spring so roots establish before intense summer heat; choose the spot carefully because it is difficult to remove once established |
|---|---|
| Sun Exposure: | Full sun to partial shade (in Florida zone 9, partial shade often improves leaf quality and reduces stress) |
| Soil Type: | Moist, fertile, well-drained soil; tolerates clay/loam if drainage is reasonable |
| Soil pH: | 6.0 to 7.5 (slightly acidic to neutral) |
| Water Requirements: | Moderate; prefers consistent moisture, especially after planting and after each cut; drought slows regrowth |
| Fertilizer Requirements: | Low to moderate; compost, aged manure, and mulch are usually enough. Heavy cutting benefits from occasional top-dressing. |
| Pruning Requirements: | Cut leaves back to 2–4 inches above the crown to harvest biomass; remove old flower stalks to reduce self-seeding |
| Growth Rate: | Fast; commonly puts on 2–3 ft of growth per season and can be cut multiple times once established |
| Companion Planting: | Excellent “support plant” near fruit trees for chop-and-drop mulch, pollinator support, and soil building (keep a clear ring around tree trunks) |
Tolerance and Hardiness
| Drought Tolerance: | Moderate once established (best growth with steady moisture); drought reduces leaf size and regrowth speed |
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| Frost Tolerance: | High; top growth may die back in cold spells, but crowns typically resprout when temperatures warm |
| Heat Tolerance: | Good; appreciates moisture and partial shade in extreme heat/humidity |
| Wind Tolerance: | Moderate; large leaves can tear in strong wind but plants usually recover quickly |
| Salt Tolerance: | Low; avoid salt spray and salty irrigation |
| USDA Plant Hardiness Zones: | 3–9 (often grown beyond this range with irrigation and shade management; performance in warm zones depends on site conditions) |
Flower and Fruit Information
| Fruit Type: | Small nutlets (seed-containing fruits typical of the borage family) |
|---|---|
| Harvest Time: | Leaves can be harvested once plants are well established; harvest when leaves are large and fully expanded (often 12–18+ inches), ideally before full flowering for the most tender biomass |
| Fruit Description: | Small, not ornamental; seeds can spread where conditions suit the plant |
| Edible Plant: | Not recommended for food use (see Health and Safety) |
| Edible Parts: | None recommended |
| Medicinal: | Historically used in traditional herbal practice, most commonly as external preparations; internal use is widely discouraged due to safety concerns (not medical advice) |
| Flower Color: | Purple, pink, to creamy-white (varies by plant/strain) |
| Flower Shape: | Drooping, bell-shaped clusters |
| Fragrance: | Light to mild |
| Flower Bloom Time: | Typically spring through summer (often March–August in warm climates, with local variation) |
| Bloom Duration: | Several weeks; bloom can repeat if plants are not cut back |
| Pollination: Self or Other? | Attracts bees and other pollinators; can self-seed if flowers set seed and seedlings are allowed to establish |
Wildlife
| Attracts: | Bees (including native bees), beneficial insects, and pollinator activity around blooms |
|---|---|
| Pollinators: | Bees are primary visitors; flowers provide nectar resources during the bloom window |
| Problematic Pest: | Common issues can include aphids, spider mites (especially in dry stress), and slugs/snails on tender growth; pressure varies by site. |
Health and Safety
| Toxic: | Yes—comfrey contains pyrrolizidine alkaloids (PAs) associated with liver toxicity when ingested; avoid internal use unless guided by qualified medical professionals |
|---|---|
| Poisonous Parts of Plant: | Leaves and roots contain PAs (levels vary); ingestion is the primary concern |
| Toxic to Humans: | Ingestion risk (liver toxicity). External use also carries cautions, especially on broken skin or prolonged use (not medical advice) |
| Toxic to Animals: | Potentially toxic if grazed or eaten in quantity (especially livestock); keep out of forage areas unless you have reliable animal-safety guidance |
| Plant Diseases to be aware of: | Powdery Mildew, Crown/Root Rot (poor drainage), Leaf Spot, and Rust in humid conditions |
Companion Planting
Comfrey is usually planted as a support species. The best companions are trees and shrubs that benefit from extra mulch, moisture stability, and pollinator activity. Below are Florida Native and Florida Friendly options with zone range, benefits, and uses that pair well with comfrey’s “biomass engine” role.
Florida Native: Beautyberry (Callicarpa americana)
Zone Range: 6–10
Benefits: Adds wildlife value and beneficial insect diversity; pairs well in mixed guild edges.
Use: Plant on the perimeter of a comfrey patch where you harvest leaves, keeping paths accessible.
Florida Native: Frogfruit (Phyla nodiflora)
Zone Range: 7–11
Benefits: Living mulch for pathways and bed edges; supports pollinators and suppresses weeds.
Use: Use frogfruit to carpet paths near comfrey harvest zones (keep comfrey crowns clear for airflow).
Florida Native: Tickseed (Coreopsis spp.)
Zone Range: Varies by species (many thrive in 8–11)
Benefits: Boosts pollinator traffic and adds bright seasonal color near comfrey blooms.
Use: Plant in sunny edges adjacent to comfrey to pull bees into the area for broader garden pollination.
Florida Friendly: Pigeon Pea (Cajanus cajan)
Zone Range: 9–11 (often grown as an annual in cooler zones)
Benefits: Nitrogen-fixer; produces quick biomass that complements comfrey mulch cycles.
Use: Plant near fruit trees with comfrey and chop pigeon pea for mulch as it grows.
Florida Friendly: Lemongrass (Cymbopogon citratus)
Zone Range: 9–11
Benefits: Strong border plant that helps define beds and provides additional mulch material.
Use: Use as a border around comfrey zones to keep harvesting tidy and contained.
Florida Friendly: Fruit Trees (Citrus, Loquat, Mulberry, etc.)
Zone Range: Varies (many thrive in Florida zone 9)
Benefits: Trees benefit from comfrey’s chop-and-drop mulch and moisture buffering in the root zone.
Use: Plant comfrey outside the trunk flare/dripline management zone; cut leaves and lay as mulch under the canopy.
Treat comfrey like a permanent infrastructure plant: pick the location first, then plant. Keep crowns clear of competing stems, cut before heavy flowering if you want fewer seedlings, and avoid tilling through comfrey patches (root fragments resprout). Use harvested leaves as mulch under trees, in compost, or as a liquid fertilizer base if you manage it safely and responsibly.
Sources & References
Reference list used for general horticultural guidance and Florida-relevant best practices (not medical advice):
- UF/IFAS Extension (Solutions for Your Life) — Florida-focused guidance on soils, mulching, irrigation, and sustainable home landscape practices.
- UF/IFAS EDIS Publication Database — research-based references for plant care concepts, pest/disease basics, and Florida best practices.
- Florida-Friendly Landscaping™ Program — water-wise and sustainable landscape recommendations that pair well with food forest design.
- USDA PLANTS Database — species-level profiles and accepted naming/synonyms used across U.S. references.
- NIH / NLM (LiverTox) — Comfrey — safety overview and toxicity concerns related to pyrrolizidine alkaloids (PAs).