Also known as Mountain Mint · 431 saves
Pycnanthemum
Pycnanthemum, the genus most gardeners know as mountain mint. We track 7 varieties; the ones most used by real gardeners.
The 7 most-saved Pycnanthemum varieties
5 species of Pycnanthemum
Each one is a parent of the varieties above.
Track your Pycnanthemum in Sow
Save the Pycnanthemum you grow and get care reminders timed to your zone.
How to grow Pycnanthemum
Whats common across all Pycnanthemum varieties in our catalog — drawn from the care records of the 7 most-grown of them.
The Pycnanthemum year
- DivideMarch, April and October100% of varieties
Divide clumps every 3-4 years to maintain vigor and manage spread.
- PruneJune86% of varieties
Cut back stems by one-third in late spring for bushier plants and delayed bloom.
- HarvestJune–September71% of varieties
Harvest foliage before flowering for best spearmint flavor.
- Spring CleanupMarch43% of varieties
Cut back old stems to the ground before new growth emerges.
Do
- Provide good air circulation to prevent fungal issues
- Mulch to conserve moisture and suppress weeds
- Water regularly during dry spells 🌱
- Prune after flowering to promote new growth
- Use organic compost to enrich soil
Avoid
- Avoid overwatering to prevent root rot ❌
- Don’t use chemical fertilizers excessively
- Do not neglect pruning to maintain shape
- Do not plant in poorly drained, chronically soggy soils where root rot can develop.
What goes wrong with Pycnanthemum
| Problem | What you'll see | What to do |
|---|---|---|
| Aphids | Sticky residue and distorted leaves | Spray with insecticidal soap or neem oil |
| Spider mites | Fine webbing and stippling on the leaves during hot, dry weather. | Increase air circulation and spray the foliage with a strong stream of water to dislodge the pests. |
| Generalist sap-sucking insects | Minor leaf distortion or sticky residue on foliage. | Monitor plants occasionally, though pest pressure is generally minimal and rarely requires intervention. |
| Deer and rabbits | Minimal to no damage. | No action needed; the volatile aromatic oils in the foliage naturally repel mammalian herbivores. |
| Powdery Mildew | White powder on leaves | Improve air circulation and apply organic fungicide |
| Powdery mildew | A white, powdery fungal coating on leaf surfaces in stagnant, humid shade. | Plant in full sun and space plants to ensure adequate air circulation around the stems. |
| Root rot | Wilting, yellowing foliage and mushy, blackened roots in waterlogged conditions. | Improve soil drainage, reduce watering, and avoid planting in low-lying, soggy areas. |
Making more Pycnanthemum
Division
- Dig up established clumps in early spring just as new growth begins.
- Use a sharp spade or knife to slice the rhizomatous root mass into sections, ensuring each has several buds.
- Replant the divisions immediately at their original depth in well-drained soil.
- Water thoroughly and keep the soil moist until new growth is actively growing.
Seed
- Tuck seeds into moist soil in early spring
- Keep soil consistently moist for 2-3 weeks
- Thin seedlings to 12-18 inches apart
Pycnanthemum questions
How many types of Pycnanthemum are there?
The Sow catalog tracks 7 distinct Pycnanthemum varieties. The most popular — ranked by 431 real gardeners — are shown first above.
What zones does Pycnanthemum grow in?
Across its varieties, Pycnanthemum covers USDA Zones 4–9. Individual varieties differ — each plant page lists its exact range, and Sow filters the catalog to your zone automatically.
When does Pycnanthemum bloom?
Most Pycnanthemum varieties bloom in mid to late summer, late summer, mid-summer. Staggering early, mid, and late varieties extends the genus's season in one bed.
Which Pycnanthemum should I choose?
Start from the most-saved varieties above — popularity across thousands of gardens is a strong signal of reliability — then filter by your zone and sun. In the Sow app you can preview any of them in a photo of your actual yard before you buy.