Fraxinus latifolia: complete guide

Overview

Fraxinus latifolia, known as Oregon ash or broadleaf ash, is a large tree native to North America. This tree grows naturally from southwestern Canada to California and reaches impressive dimensions. With its broad leaflets and handsome structure, it is a valuable addition to large gardens and park landscapes.

Appearance and bloom

This impressive tree grows 15-20 meters tall and forms an open, airy crown. The leaves are compound, pinnate, with up to nine broad leaflets per leaf. These leaflets are dark green and provide substantial shade. Flowers are inconspicuous and greenish, followed by ornamental winged fruits (samaras) attractive to birds.

Ideal location

Place Oregon ash in locations with ample space. This tree is very large and requires significant room. Ideal for large gardens, parks, and landscapes. Prefers full sun to light partial shade. This tree thrives best in moist riparian valleys.

Soil

Fraxinus latifolia grows best in well-drained soils. Accepts both acidic and neutral terrain (pH 4.8-7.0). Moist soil preferred, but reasonably drought-tolerant once established. Organic matter adds value.

Watering

During the growing season, regular water preferred. Mature trees very drought-tolerant. Young trees benefit from consistent moisture in dry summers. Avoid excessive water and waterlogging.

Pruning

Oregon ash requires moderate pruning. Prefer to form the crown in young years by removing competing stems. Lower branches can be removed for clearance. Prune during dormancy.

Maintenance calendar

February-March: Formative pruning, remove dead branches April-May: Leaf growth, no feeding needed June-August: Flowering and fruiting, water in drought September-October: Fall color, seed dispersal November-January: Dormancy, plan future pruning

Winter hardiness

Fraxinus latifolia is winter-hardy to about -15°C. Better in temperate climates. In harsher zones, shelter helps.

Companion plants

Under Oregon ash shade grows well. Suitable shade-lovers: ferns, shade-tolerant perennials, Hedera helix. Also works with low shrubs and groundcovers.

Closing thoughts

Oregon ash offers impressive stature and beautiful foliage for large gardens. Perfect shade and wildlife tree. Purchase from specialized tree nurseries.

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