How to Grow: Overwinter Perennial Herbs

Learn about perennial herbs, including how to grow and overwinter them.

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I remember on one of my first trips to California I was walking along a garden and gently brushed my hand along this hedge. The smell surprised and delighted me. It was my first experience with rosemary. This perennial herb is a great edible landscape shrub in zones 7 and warmer. However, in Vermont it falls into the category of herbs that need protection to survive.

Rosemary, scented geraniums, and lavender of some of the tender perennial herbs that need help overwintering in our cold climate. While some lavenders, such as ‘Munstead’, will survive outdoors if protected with bark mulch in November, scented geraniums and rosemary need to be brought indoors. Here’s what to do. Move potted herbs to a shady location outdoors now. Give plants a week to acclimate to these low light conditions. Then move them indoors into a south facing window. Geraniums will grow fine, getting leggy and needing periodic cutting back. However, rosemary needs cooler temperatures and higher humidity than found in most homes. Place rosemary pots on a tray filled with a layer pebbles and water in a 50 degree, sunny room. Keep the soil barely moist all winter and then move the plants back outdoors next spring.

Now for this week’s tip, leave the flower heads of echinacea, rudbeckia, and tithonia on the plants after their done blooming. Small birds, such as goldfinches, will to eat the seeds while you enjoy them perching in your garden.

From the Vermont Garden Journal on Vermont Public Radio.