Magnolia care guide: when & how to prune, fertilize and spray

When: 2–6 weeks after the last spring frost.

• zones 3–5: about May 24 – Jun 21
• zones 6–7: about Apr 29 – May 27
• zones 8–10: about Mar 11 – Apr 8

Magnolias set next year's buds over the summer and don't compartmentalize wounds well. Prune only what's necessary.

1. Remove dead, crossing and damaged branches only.
2. Never top or make large cuts. Remove small branches back to their point of origin.

When: 2–6 weeks before the last spring frost.

• zones 3–5: about Mar 29 – Apr 26
• zones 6–7: about Mar 4 – Apr 1
• zones 8–10: about Jan 14 – Feb 11

Smothers overwintering magnolia scale before they hatch. It's the lowest-toxicity insect control you can do all year.

1. Pick a calm, dry day between 40°F and 70°F (4–21°C) with no freeze forecast for 24 hours.
2. Mix the oil at the label's dormant rate.
3. Coat every branch, crotch and bark crevice until it drips.
4. Spray before buds open. Oil on tender green tissue can burn it.

What to use: 🌿 Horticultural / dormant oil (e.g. Bonide All Seasons Oil)

Caution: Don't use within 2 weeks of a sulfur spray. Don't spray blue spruce or other blue conifers; oil strips their color.

When: 2–6 weeks after the last spring frost.

• zones 3–5: about May 24 – Jun 21
• zones 6–7: about Apr 29 – May 27
• zones 8–10: about Mar 11 – Apr 8

Mulch keeps roots cool and moist, suppresses weeds and slowly feeds the soil. Applying it after the soil warms lets roots wake up first.

1. Spread 2–3 in (5–7 cm) of mulch over the root zone.
2. Keep mulch 2–3 in (5–7 cm) away from stems and trunks. Mulch piled against bark invites rot and rodents.
3. Don't go deeper than 3 in (7 cm) in total. Too much mulch suffocates roots.

What to use: 🌿 Shredded hardwood or pine bark mulch