Growing Peppermint: How to Identify Mutations & Maximize Harvest

Mint is the “bully” of the herb garden. I always tell my clients: “Friends don’t let friends plant mint in the ground.” It spreads via underground runners (rhizomes) and will take over your yard in a single season.

But today, we’re looking closer at this aggressive grower. Sometimes, you might spot something odd—a stem with white stripes, or leaves that look different. Welcome to the world of plant mutations.

Common Mint Mutations (Variegation)

One of the most exciting things to find in a patch of green peppermint (Mentha × piperita) is variegation. This happens when a random genetic mutation causes some cells to lack chlorophyll.

• What to look for: A single stem producing leaves with white/cream edges or splashes of white.
• What to do: If you like it, propagate it! Take a cutting of just that mutated stem. If you root it, you might create your own “clone” of a variegated mint plant. This is how varieties like “Pineapple Mint” (a variegated apple mint) are maintained.

”Reverting” to Spearmint?

Peppermint is actually a sterile hybrid cross between Water Mint and Spearmint. Since it’s sterile, it doesn’t grow true from seed (seeds sold as “peppermint” are usually just spearmint). Sometimes gardeners feel their peppermint has “lost its punch.” This isn’t usually a genetic mutation, but environmental:

• Low Sun: Reduces essential oil production (less menthol flavor).
• Old Soil: Mint is a heavy feeder. Depleted soil leads to weak flavor.

Maximizing Your Harvest

To get the bushiest, most flavorful mint:

1. The “Containment Field”

Always grow mint in a pot. If you want it in a garden bed, sink the pot (with the bottom cutting out, but deep sides) into the ground to create a wall against the rhizomes.

2. Pinch, Don’t Pull

Never just pull off single leaves. Pinch the stem just above a leaf node (where leaves grow out).

• Result: Two new stems will grow from that cut point.
• Benefit: You turn one stem into two, then two into four. This prevents the plant from getting “leggy” and flowering. Once mint flowers, the leaf flavor becomes bitter.

3. Sun and Water

Mint loves water. It’s naturally a riverbank plant. Keep the soil consistently moist. It prefers full morning sun but appreciates some shade in the scorching afternoon heat.

Uses for Fresh Peppermint

• Tea: Fresh leaves steeped in hot water are superior to dried tea bags.
• Pest Control: Mice and spiders hate the smell of strong peppermint oil.
• Mojitos: Obviously!

Common Mint Pests

Even the tough mint plant has enemies. Watch out for these:

1. Spider Mites: Look for tiny webs and yellow stippling on leaves. Wash them off with a strong blast of water or use Neem oil.
2. Mint Rust: Small, bright orange spots on the undersides of leaves. This is a fungus. Remove infected leaves immediately and water at the soil level, keeping foliage dry.

How to Preserve Your Harvest

You will likely have more mint than you can use. Don’t let it go to waste!

• Drying: Bundle stems together and hang them upside down in a dark, airy place for a week until crispy. Strip the leaves and store in jars.
• Freezing: This preserves the flavor better than drying. Chop the leaves, place them in an ice cube tray, fill with water, and freeze. Pop a “mint cube” into your tea or lemonade later!

Grow it wild, but grow it contained!