What to Plant in March in Zone 7

Perennials Break Ground

This is the month the permanent crops join the annuals. Asparagus crowns, rhubarb divisions, blueberry and blackberry bushes, and bare-root strawberries all go in now, six to eight weeks ahead of your last frost. None of them mind a light freeze once planted; what they mind is sitting in a nursery pot with roots circling for another month.

Leave asparagus alone this first year. Cutting spears before the crowns have had a full season to build root reserves is the fastest way to weaken a planting that should otherwise produce for 15 years or more.

Blueberries need acid soil, ideally a pH between 4.5 and 5.5. Test before you plant; correcting pH after the bush is in the ground with roots already spread takes years of amendment instead of one bag of sulfur worked into the hole.

Rhubarb divisions planted this month should not be harvested at all in their first year. Pulling stalks early robs the crown of the energy it needs to build a root system strong enough to keep producing for a decade or longer.

Space gooseberry and currant bushes at least 4 feet apart in every direction. Powdery mildew actually favors warm, dry afternoons with a dewy night behind them, not soggy conditions, so crowding does its damage by blocking the breeze that dries those dewy leaves off each morning; a little airflow closes that window at almost no cost.

The Cool Crops Start Their Clock

Everything that opened in February, spinach, kale, cabbage, broccoli, peas, potatoes, and the rest, is now on a countdown. Most of that list closes out this month, since April's heat pushes bolt-prone greens toward flower stalks faster than they can be resown.

Herbs join the table for the first time this month too: dill, thyme, oregano, and chives can all go in as soon as nights hold above 40. Direct-sow dill rather than transplanting it; the taproot resents disturbance and a transplanted seedling often bolts within weeks instead of building leaf.