Frangula alnus
Alder buckthorn, Black dogwood
Also known as Alnus frangula, Rhamnus frangula
- Height × spread
- 2.5m – 2.5m × 1.5m – 1.5m
- Position
- Full sun
Availability
Please ask in store about availability
Many plants are seasonal. Call 01234 567890 to check current stock.
About this plant
This is the remaining representative of its genus, the other species having been reallocated to the genus Rhamnus. The species makes a large shrub or a small tree. The species carries red fruits that turn black with age, both colours being present at the same time. There are a number of cultivars available. These include a form with cut leaves.
- Foliage colour
- Green
- Fruit colour
- Black
- Variegated
- No
- Scent
- No
- Shape
- Cone
- Height
- 2.5m – 2.5m
- Spread
- 1.5m – 1.5m
- Season of interest
- Autumn
- Evergreen
- Deciduous
- Sun or shade
- Likes full sun, tolerates part shade
- Soil type
- Loam (normal), Sandy soil
- Soil pH
- Acid (ericaceous)
- Drainage
- Moisture retentive soil
- Winter hardiness
- Varies, most are hardy
- Borders & containers
- Borders
- Use for
- Structural, Bee attraction, Butterfly attraction, Bird attraction
- Hazards
- Yes, some poisonous
Spring
Spring - late · Outdoors
Feed with slow release fertiliser
Apply a general purpose slow release fertiliser, spreading it around the root area of the plant as it is coming into growth. (Or apply a liquid feed at regular intervals throughout the growing season.)
This is a simple way to provide a nutrient boost as a single annual procedure.
Spring - late · Outdoors
Feed with sequestrol
If plants are acid loving and grown in soil with little acidity, or in a container, or are watered with limey tap water an annual feed with sequestrol (iron chelate) is highly beneficial. Follow guidelines on the packet. Will also 'blue-up' hydrangeas.
For hydrangeas that have good blue flowers in acid soil, this product can be used with alkaline soil to turn the flowers blue. This is most effective when the soil is neutral or just slightkly alkaline.
Spring-Autumn · Outdoors
Water to keep the soil moist
For best results, this plant needs soil that is always moist. Water deeply and regularly as soon as soil appears dry. Even for established plants in the ground, a dry week can cause problems with some soils. Check plants in pots more often, especially in hot weather. Or install an automatic irrigation system which will do the hard work for you, even when you are away on holiday.
Without regular watering some plants never fully regain their beauty.