As a forest garden designer, I often focus on trees, upright shrubs, and canes when thinking about obtaining a yield of fruit. But even the ground cover layer in a forest garden can provide a yield of this type. Fruiting ground cover plants are useful for suppressing weeds and unwanted growth, conserving moisture, and reducing evaporation from the soil. They can also fulfill a range of other ecosystem functions.
Before planting any new ground cover, check with your regional University Extension office or a local garden center expert for advice on plants that may be invasive in your area.
Perhaps the best known fruiting ground cover plant is strawberry. But in a forest garden or food forest, garden strawberries (Fragraria x ananassa) are not always the best option. Instead, I like to use strawberries that are more tolerant of the dappled shade beneath the trees. Alpine strawberries, wild strawberries, woodland strawberries, musk strawberries—there are plenty to choose from. Which one is best for you depends on where you live.
In the United States, you might opt for one of the parents of most cultivated garden strawberries, Fragraria virginiana, that grows in USDA zones 3-7. In Europe, you would likely opt for one of the varieties of Fragraria vesca (USDA zones 4-8). There is also a Fragraria vesca in California and the southwestern U.S. Another option in Europe is the musk strawberry, Fragraria moschata (USDA zone 5-9), though the fruits tend not to form as freely.
Ground Cover Rubus
Moving beyond strawberries, there are also plenty of other ground cover fruiting plants which are not particularly well known. Amongst these, one that I find the most useful and widely applicable is the ground cover Rubus (also known as creeping raspberry), which spreads out to form dense ground cover rather than growing in a vertical form.
These species can be very helpful, sometimes even in deeper areas of shade and in otherwise tricky conditions. They can be very vigorous and spread quickly to give good ground cover, which is useful in the establishment of larger sites. Care should be taken, however, when choosing these for smaller gardens.
Some ground cover Rubus to consider include:
- Rubus tricolor, which can cope with deeper shade below conifers (USDA zones 6-9)
- Rubus nepalensis (USDA zones 7-10)
- Rubus pentalobus “Emerald Carpet” (USDA zones 7-9)
- R. pentalobus x R. tricolor “Betty Ashburner” (must be pollinated with either parent for fruits to form)
Another Rubus that can form ground cover below trees and shrubs is the dewberry, Rubus Caesius (USDA zones 4-8). There is also the cloudberry, R. chamaemorus (USDA zones 2-4).
Ground cover Rubus can also be useful in many temperate climate designs.
Other Fruiting Ground Covers
Strawberries and ground cover raspberries are not the only low-growing and spreading fruiting ground cover plants that I like to consider for a forest garden. Other interesting plants which may work in a forest garden or around its sunny fringes include:
- Bilberries (Vaccinium myrtillus, USDA zones 3-7)
- Blueberries (e.g. Vaccinium angustifolium, USDA zones 2-6)
- Cranberries (Vaccinium macrocarpum on acidic, damp sites, USDA zones 2-7)
- Lingonberry (Vaccinium vitis-idaea and other Vaccinian ssp, USDA zones 3-8)
- Huckleberry (Gaylussucia brachycera, USDA zones 5-9)
- Bearberry (Archostaphylos uva-ursi and Archostaphylos alpina, USDA zones 4-8)
- Crowberry (Empetrum nigrum, USDA zones 3-8)
- Salal (Gaultheria shallon, USDA zones 6-9)
- Wintergreen (Gaultheria procumbens, USDA zones 3-6)
While strawberries and Rubus types are most useful in the widest range of settings, there are plenty of other interesting fruiting ground cover options to consider. It is always essential to think about the climate and conditions in your particular area before choosing any plants for your forest garden.
Many of the above need very specific soil and environmental conditions to thrive, so not all will be suitable for your particular location, even if you live in a hardiness zone where they can theoretically survive. Many, for example, need damp, boggy conditions or an acidic soil. Consider these factors before you make your choices.
Using ground covers is just one more important strategy I use for making the most of a space and maximizing the yield from a forest garden.