how to control mint in garden

How to Control Mint in the Garden

Mint is a popular and versatile herb that adds wonderful flavor and fragrance to many dishes. However, its spreading nature can quickly turn mint from a delightful garden plant to an invasive weed taking over your yard. To grow mint successfully, it’s vital to control its growth and prevent its aggressive roots and runners from colonizing your garden beds or lawn. With some strategic planting techniques and vigilant maintenance, you can keep your mint contained and avoid a minty garden nightmare.

Choosing the Right Mint Variety

The first step in managing mint is selecting the right variety for your needs. The most aggressive types that require diligent control are spearmint (Mentha spicata) and peppermint (Mentha piperita). More docile options are orange mint (Mentha citrata) apple mint (Mentha suaveolens) and pineapple mint (Mentha suaveolens ‘Variegata’). Corsican mint (Mentha requienii) is a low, creeping variety that spreads slowly and is easier to contain. Also consider compact garden mints bred specifically not to spread invasively, like Mint ‘Mojito,’ and sterile hybrids that don’t produce viable seeds or runners.

Planting Mint Properly

Even when you choose a non-aggressive mint, it still requires preventative care at planting time. Always give mint its own separate space in the garden rather than mixing it in with other plants. The most foolproof method is planting mints in bottomless containers sunk into the ground. This confines wandering roots while still allowing the plant to grow normally. Bury standard plastic nursery pots or other small containers, like metal buckets, at least 8 inches deep. For larger plantings, border the mint bed with planks, cinder blocks, or another barrier planted 10-12 inches deep. If planting mint in an in-ground bed without physical barriers, allow at least 2-3 feet space on all sides between the mint and other plants.

Caring for Container Mints

Growing mint in above-ground pots is ideal for control. Choose containers at least 12 inches wide and deep to accommodate the plant’s vigorous root system. Make sure the pot has drainage holes to prevent soggy soil. Fill the container most of the way with high-quality potting mix, plant the mint, and water well. As the mint becomes established, check the container regularly to see if roots are escaping from the drainage holes. If so, prune them away to keep the plant contained. Repotting annually helps reduce spreading tendencies as well. Divide congested mint clumps in early spring and repot only the most vigorous sections of roots and crown.

Ongoing Maintenance

Even when mint is properly planted, it still requires vigilant maintenance to keep growth in check:

• Inspect weekly and prune anytime mint plants wander beyond their designated space.

• Cut off runners traveling on top of the soil at least 6-12 inches before the end to prevent new rooting.

• Pull up underground runners carefully to get the entire root and stem.

• Mulch around mint beds to mark its territory clearly.

• Set pitcher pumps, oscillating sprinklers or soaker hoses rather than overhead watering to avoid scattering seeds.

• Remove spent blossoms before they set seeds.

• Top dress container plantings yearly with fresh soil or compost, but avoid high-nitrogen fertilizers that fuel excessive growth.

• Divide potted mints every 2-3 years to rejuvenate and contain them.

Eliminating Out of Control Mint

Sometimes mint plants escape their boundaries and get completely out of hand. Eliminating unruly mint entirely usually requires persistence. Digging up the plant helps, but some roots inevitably get left behind and regrow. Smothering with mulch or landscape fabric slows mint down but doesn’t kill it. Repeated mowing and pruning of top growth eventually weakens the plant, but it takes time.

For the quickest control, most gardeners turn to herbicides. Systemic products that kill right down to the roots work best. Glyphosate (Roundup and others) is effective but also harms surrounding plants. Vinegar or clove oil sprays only injure above-ground parts and regrowth quickly appears. With any treatment, repeatedly treat regrowth for best results eliminating invasive mint.

Prevention is Key

While managing unwelcome mint invasions takes effort, preventing mint from spreading out of control in the first place is much easier. Give all mint plants plenty of breathing space, grow in containers above or below ground, and pay close attention to keeping growth contained within its designated area. With smart preventative planting and vigilant care, you can enjoy the wonderful benefits of fragrant, flavorful mint without it taking over your garden.