Crab apple 'Red Sentinel'

Sun

Full sun gives the best flowering and fruiting; tolerates light partial shade.

Water

Water regularly while establishing. Established trees tolerate short dry spells, but benefit from deep watering during prolonged drought.

Soil

Moderately fertile, well-drained soil that retains some moisture; tolerates clay, loam and sandy soil, and a broad range of soil pH. Avoid waterlogged ground.

Height

15-25 ft (4.5-7.5 m)

Spread

13-20 ft (4-6 m)

Flowers

Mid- to late spring; pink buds open to white flowers.

Foliage

Oval green leaves, sometimes developing yellow autumn colour before falling.

Growth

Moderate; ultimate size and growth depend partly on the rootstock.

Care needed

Low

• Pollinators
• Cold hardy
• Disease resistant
• Wildlife
• Low allergen

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Easy

Toughness

Very tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   7 ft (2 m)

2. After 1 year

   7 ft (2.2 m)

3. After 2 years

   8 ft (2.4 m)

4. After 3 years

   9 ft (2.6 m)

5. After 5 years

   10 ft (3 m)

About 20 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Toxic

Growth rate

Moderate

• Plant with the root flare at soil level and any graft union above the soil.
• Water deeply during dry weather for the first two growing seasons, wetting the whole root area.
• Apply a 2-3 in (5-8 cm) mulch over the root area, keeping it clear of the trunk.
• Keep grass and weeds away from the young tree's base; feed in spring only if growth is weak or soil is poor.
• Stake only if the tree is unstable, use a flexible tie, and remove the support once roots hold it firmly.

Pruning. Prune lightly in late winter while dormant, removing dead, damaged and crossing branches and any shoots from below the graft. Keep the natural crown rather than clipping it; remove suspected fire blight promptly in dry weather using disinfected tools.

Autumn

Plant while the soil is workable, water thoroughly and mulch; in very cold climates, plant in spring instead.

Late winter

Check stakes and ties, remove suckers and carry out any necessary light pruning.

Spring

Refresh mulch and check new leaves and blossom for aphids or disease.

Summer

Water young trees deeply during dry spells and keep the base free of grass.

Autumn

Remove fallen leaves if apple scab has been troublesome, but leave healthy fruit for winter display and birds.

Winter

Check young trunks for rabbit, vole or deer damage and fit a suitable guard where needed.

• Use as a specimen in a lawn, allowing enough space for the mature crown.
• Underplant with snowdrops, crocuses and other spring bulbs for a layered spring display.
• Place beside a winter-view window, where the persistent red fruit can be seen clearly.
• Combine with mixed shrubs and perennials in a wildlife-friendly garden.
• Plant near an ornamental or productive orchard as a flowering accent and potential pollination partner for compatible apples.

Garden styles it suits: English country, Cottage garden, Traditional, Wildlife garden, Backyard orchard and Winter interest.

Plant it with: Snowdrops, Crocuses, Hardy geraniums, Hellebores, Japanese anemones and Lady's mantle.

Wildlife: Flowers provide pollen and nectar for bees and other insects. Birds eat the small apples, often later in winter after the fruit softens; the branches also provide shelter and perches.

• Apple scab can cause dark leaf spots and early leaf fall, although this cultivar generally has good resistance. Remove infected fallen leaves and maintain an open crown.
• Fire blight causes blackened blossom and hooked, dying shoots. Cut back well into healthy wood in dry weather, disinfect tools between cuts and seek local advice if damage is extensive.
• Aphids can curl young leaves and leave sticky honeydew. Encourage natural predators and wash small colonies off with water; avoid spraying open flowers.
• Drought and competition from lawn grass can cause poor establishment and fruit drop. Keep a mulched, grass-free area around the trunk and water deeply during dry spells.

Apple flesh is not known to be toxic to people, cats, dogs or horses, though eating much crab apple fruit can cause stomach upset. Seeds, leaves and stems contain cyanogenic compounds; substantial ingestion, especially of chewed seeds or wilted foliage, can cause serious poisoning. Keep horses away from prunings and seek medical or veterinary advice after significant ingestion.

• Crab apple 'John Downie' (Malus 'John Downie')

  Its fruits are more elongated, often pear-shaped, and orange-yellow flushed with red rather than uniformly glossy red.

• Crab apple 'Golden Hornet' (Malus × zumi 'Golden Hornet')

  Has conspicuous golden-yellow fruits rather than red ones.

• Crab apple 'Red Jade' (Malus 'Red Jade')

  Also bears red fruit, but has a distinctly weeping crown with arching, drooping branches.

Malus is the Latin name for an apple tree, and robusta means strong or robust.

Propagation. Usually propagated by grafting in late winter or budding in summer onto a suitable apple rootstock. Seedlings will not reliably retain the cultivar's characteristics, and rootstock suckers are not 'Red Sentinel'.

Accepted botanical name

Malus robusta

Sources: GBIF (CC BY 4.0). The care and design notes are LandscapeGPT's own.