Garden Care Guide

Oregon Grape Care

Mahonia aquifolium

A thorny, evergreen shrub that is ideal for shaded and partially shaded areas. It is decorative with its bright yellow flower clusters, bluish-black fruits and leaves that turn bronze-purple in winter. It likes moist, well-drained, acidic soils rich in organic matter.

Hardy · -25 °C / -13 °F

Monthly care calendar

Timings are for a temperate Northern Hemisphere climate. In warmer areas tasks start earlier, in colder areas later; in the Southern Hemisphere shift them by six months.

January
  • Pruning: Not needed; the flower buds are ready. Only remove broken branches.
  • General care: Check the mulch in the root zone.
February
  • General care: Toward the end of the month, flowering may begin in temperate regions.
  • Frost risk: Hardy, but open flowers may be affected by severe frost.
March
  • Watering: Water a newly planted specimen more often than established plants during its first year, as its root system is still shallow.
  • Fertilizing: After flowering, apply acidic fertilizer or compost, to the soil, 30-40 g/m²; do not overapply.
  • Pruning: The best time for pruning is as soon as flowering ends. You can rejuvenate the plant by cutting old branches at the base.
  • General care: Suitable period for planting and transplanting. Flowering begins.
  • Pests & diseases: Check the leaves for leaf spot diseases and rust (orange spots).
  • Frost risk: Late frosts can damage flowers.
April
  • Watering: Water a newly planted specimen more often than established plants during its first year, as its root system is still shallow.
  • Fertilizing: If fertilizing has not been done, it can be done at the beginning of the month.
  • Pruning: The last chance for pruning is the beginning of the month.
  • Plant protection: If aphids or powdery mildew are seen, use a suitable insecticide/fungicide at the label dose.
  • General care: Suitable period for planting and transplanting. Flowering continues.
  • Pests & diseases: Be careful about rust (Pucciniales). If the leaves are yellowing, give an iron supplement.
May
  • Watering: Water a newly planted specimen more often than established plants during its first year, as its root system is still shallow.
  • Pruning: Prune as soon as flowering ends. Next year's flower buds form over the summer; late pruning reduces flowering. After flowering is complete, shorten the branches. On low-growing forms, only dead branches are removed. Use gloves because of its thorny structure.
  • Plant protection: If symptoms spread and treatment is needed, consult a licensed plant-protection supplier or an agronomist. Plant protection products are regulated; follow local rules.
  • General care: Good time for planting and transplanting.
  • Pests & diseases: If you see black spots with yellow halos on the leaves (black spot), collect the diseased leaves and remove them from the garden; the disease overwinters in fallen leaves.
June
  • Watering: In a long drought, water deeply once a month.
  • Plant protection: If symptoms spread and treatment is needed, consult a licensed plant-protection supplier or an agronomist. Plant protection products are regulated; follow local rules.
  • General care: Regular watering is important to prevent leaf scorch, especially in sunny spots.
  • Pests & diseases: If you see black spots with yellow halos on the leaves (black spot), collect the diseased leaves and remove them from the garden; the disease overwinters in fallen leaves.
July
  • Watering: In midsummer, deep watering every 15-20 days is enough. Established plants (over 2 years old) do not need watering in most years. Water the area around the roots to a depth of 15-20 cm.
  • Plant protection: If symptoms spread and treatment is needed, consult a licensed plant-protection supplier or an agronomist. Plant protection products are regulated; follow local rules.
  • General care: Keep it in a position sheltered from midday sun; scorching at the leaf edges is a sign of burn.
  • Pests & diseases: In hot and dry weather, look on the undersides of the leaves for fine webbing and speckled yellowing (spider mites). Washing the leaves during the cool hours reduces their numbers.
August
  • Watering: In midsummer, deep watering every 15-20 days is enough. Established plants (over 2 years old) do not need watering in most years. Water the area around the roots to a depth of 15-20 cm.
  • Plant protection: If symptoms spread and treatment is needed, consult a licensed plant-protection supplier or an agronomist. Plant protection products are regulated; follow local rules.
  • General care: The fruits (grape-like) ripen and turn black. They are attractive to birds.
  • Pests & diseases: In hot and dry weather, look on the undersides of the leaves for fine webbing and speckled yellowing (spider mites). Washing the leaves during the cool hours reduces their numbers.
September
  • Watering: In a long drought, water deeply once a month. Water newly planted specimens more often than established plants during the first year; the root system is still shallow.
  • Plant protection: If symptoms spread and treatment is needed, consult a licensed plant-protection supplier or an agronomist. Plant protection products are regulated; follow local rules.
  • General care: Good time for planting and transplanting.
  • Pests & diseases: If you see black spots with yellow halos on the leaves (black spot), collect the diseased leaves and remove them from the garden; the disease overwinters in fallen leaves.
October
  • Watering: Water a newly planted specimen more often than established plants during its first year, as its root system is still shallow.
  • General care: Good time for planting and transplanting.
  • Pests & diseases: Remove diseased leaves.
November
  • Watering: Water a newly planted specimen more often than established plants during its first year, as its root system is still shallow.
  • General care: Good time for planting and transplanting.
December
  • General care: Evergreen leaves continue to lose water in winter. Water thoroughly once before the soil freezes.

The care advice on this page is general and for information only; it is not professional advice. Plant age, soil and your garden’s microclimate can change the outcome. Plant protection products are mentioned only as general information; they are regulated, and the choice, dose and timing must be decided by a qualified professional under local rules. Consult a landscape architect or agronomist before applying.

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