The taxonomy of Crataegus species has historically been very confused, with over 1,200 different species recognized by some authors in the past. This number has been gradually and very significantly reduced, especially since the publication of several regional studies carried out since the late 1980’s, and current thinking is that the final number could be below 150 distinct species[]. Many of the genera that were included in this database prior to 2017 will now be treated as synonyms or subspecies, and it is likely that a number of other currently accepted species will also receive that fate once a complete revision of the genus (underway in 2015) has been published.

Common Name: Washington Thorn

General Information

Crataegus phaenopyrum is a thorny, deciduous tree with a dense, rounded head of leafy branches; it can grow from 4 - 10 metres tall, usually with a single, slender trunk[, , ].
The plant is harvested from the wild for local use as a food. It is often grown as an ornamental, where it can be used to make a thorny hedge.

Known Hazards

None known

Botanical References

, ,

Range

Eastern N. America - Oregon, Michigan and Pennsylvania, south to Louisiana and Florida

Habitat

Thickets, open woods[] and banks of streams in rich soils[]. Woodland edges, gaps, scrub, damp locations; at elevations from 10 - 300 metres[]. Found in woodlands on rich soil, generally in moderate but not very heavy shade[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Deciduous Tree
Height	10.00 m
Pollinators	Midges
Cultivation Status	Ornamental, Wild

Cultivation Details

Crataegus phaenopyrum is a very cold-hardy plant, able to tolerate temperatures down to around -25°c when dormant[].
Crataegus species are generally very easily cultivated plants, growing best in full sun to medium shade and preferring a well-drained but moisture retentive loamy soil, though they are not usually fussy[, ]. This species grows well on a chalk soil and also in heavy clay soils[]. Once established, many species can tolerate a range of difficult conditions including drought; excessively moist soils; exposed, windy, maritime conditions; and atmospheric pollution[]. Notes on the plants habitat above may give more ideas on this[].
Trees growing in a sunny position generally produce more and better quality fruit than trees growing in the shade[].
This species is one of the most widely planted ornamentals in the genus, being elegantly tree-like and possessing beautiful, remarkably rust-resistant foliage as well as attractive flowers and fruit. Several cultivars are known[, , ].
The flowering season of the Washington thorn is the latest of all North American hawthorns[].
Crataegus species often hybridize freely with other members of the genus[, ]. This statement is not fully accurate; at least in the wild most Crataegus species usually breed true and only occasionally hybridize - in addition, any hybrids are usually putative[].
Many Crataegus species are very variable with regard to fruit size and quality. Seedlings, even if obtained from a good fruiting form, can often be disappointing - though they can also be an improvement on the original form. The most reliable way of obtaining a good fruiting form is by grafting from a known good tree, or obtaining a named cultivar from a reliable source[].
Seedling trees take from 5 - 8 years before they start bearing fruit, though grafted trees will often flower heavily in their third year[].
Seedlings should not be left in a seedbed for more than 2 years without being transplanted[].
The flowers have a foetid smell somewhat like decaying fish. This attracts midges which are the main means of fertilization. When freshly open, the flowers have more pleasant scent with balsamic undertones[].

Edible Uses

Fruit - raw or cooked[]. A dry flesh[]. Very small, the globose, glossy-vermilion fruit is about 5 - 8mm in diameter, it often hangs on the tree all winter[, ]. There are up to five fairly large seeds in the centre of the fruit, these often stick together and so the effect is of eating a cherry-like fruit with a single seed[].

Medicinal

Although no specific mention has been seen for this species, the fruits and flowers of many hawthorns are well-known in herbal folk medicine as a heart tonic and modern research has borne out this use. The fruits and flowers have a hypotensive effect as well as acting as a direct and mild heart tonic[]. They are especially indicated in the treatment of weak heart combined with high blood pressure[]. Prolonged use is necessary for it to be efficacious[]. It is normally used either as a tea or a tincture[].

Agroforestry Uses:

A thorny plant that responds well to trimming and pruning, it can be used to make an intruder-proof hedge or barrier[].

Other Uses

The wood of Crataegus species is generally of good quality, though it is often of too small a size to be of much value. It usually has a red-brown heartwood with a thick band of lighter-coloured, usually pale sapwood. The wood is heavy, extremely hard, tough and close-grained. Where wood of suficient diameter is found it is often greatly prized for use in turnery, and has traditionally been used for purposes such as making tool handles, mallets and other small items[, ].

Propagation

Seed - this is best sown as soon as it is ripe in the autumn in a cold frame, some of the seed will germinate in the spring, though most will probably take another year. Stored seed can be very slow and erratic to germinate, it should be warm stratified for 3 months at 15°c and then cold stratified for another 3 months at 4°c[]. It may still take another 18 months to germinate[]. Scarifying the seed before stratifying it might reduce this time[]. Fermenting the seed for a few days in its own pulp may also speed up the germination process[]. Another possibility is to harvest the seed 'green' (as soon as the embryo has fully developed but before the seedcoat hardens) and sow it immediately in a cold frame. If timed well, it can germinate in the spring[]. If you are only growing small quantities of plants, it is best to pot up the seedlings as soon as they are large enough to handle and grow them on in individual pots for their first year, planting them out in late spring into nursery beds or their final positions. When growing larger quantities, it might be best to sow them directly outdoors in a seedbed, but with protection from mice and other seed-eating creatures. Grow them on in the seedbed until large enough to plant out, but undercut the roots if they are to be left undisturbed for more than two years.