Plants

A Polyculture for Herbal Tea, Salad, Fruits and Wildlife

Refreshing vitalizing herbal teas, a living first aid cabinet, wildlife habitat, beauty, and interest throughout the year, with some strawberries, currants, and salad leaves to boot! This Polyculture is ideal for small gardens taking up no more than approx 6m2 but also working well in a larger space as a beneficial island that fills a gap within the wider garden ecosystem of fruit, nut, and ornamental trees.

During this post, we’ll take a look at the species included, their function and uses, how to choose a site for the polyculture,  how to manage the plants, when to harvest, and you’ll find some planting plans with guidance on spacing. 

 

Species Overview 

All the plants in this polyculture (apart from Agastache foeniculum) are native to Europe and all are well adapted to the climate and ecology of the Northern Temperate zone. We have been growing these plants in hardiness zone 6 for years, and all the plants have tolerated temperatures down to -15C and less. Most of the plants are well adapted to dry conditions and will survive on the average annual rainfall of 560mm. That said, we want the plants to thrive, and irrigating the plants during periods of drought will make for thriving plants. Irrigation is also necessary if you would like a decent yield of strawberries and black currants particularly when the fruits are forming.

The plants are well suited to most soils excluding heavy clay, waterlogged soils, and soils with pH in the extremes of acidity or alkalinity. If you have these types of soils they can of course be amended, but selecting plants to suit soils is a better option, both ecologically and economically.

 

Functions and Uses

My goals when designing this polyculture were that every plant included can be used for making both fresh and dried herbal teas and that as a community the planting scheme should benefit the garden ecosystem. Below is a chart indicating the other uses and beneficial functions of the plant community.

 

Choosing the site for the Polyculture

When choosing the position in your garden for this polyculture the main thing to consider is the positioning of your bed in relation to the sun and to match this up with the individual needs of the plants, ensuring that the sun-loving plants are on the Southern facing side and the shade tolerant plants are on the North. (light needs listed below)
Depending on how much annual precipitation you receive in your area, it may also be important to position the bed so that it can passively collect water from rainfall e.g with a slight dip in the middle or at the base of a slope laid out on contour. This is a relevant practice in Bulgaria where we can expect 8-12 weeks without significant rain during high summer, but not so relevant in the UK. The area where the rainwater accumulates should feature the plants that are more water-demanding and obviously the area that will receive the least amount of water should be planted with drought-tolerant species.(water needs listed below).
This self-replenishing Chai Store/Salad Bar is there to be picked so making it easily accessible to you is an important factor when choosing its position. Once you have established the footprint of your bed you can begin to build it. This can be as simple as piling up topsoil mixed with well-rotted compost to a height of 50-70 cm in the desired shape and bordering your mound with large rocks or boulders laid in a small trench around the soil. Simple if you have lots of rocks and boulders nearby which we do. You could also build a retaining wall first and then infill it with your topsoil and compost. Bear in mind the bulk of the soil will reduce over the first 3-6 months as the soil settles.

 Chai Polyculture – Built and planted in November 2012

Plant selection

Aside from selecting plants in relation to their space, light, and water need their ecological characteristics are also considered.
Achillea millefolium – Yarrow is very drought tolerant and I use these plants evenly spaced in gaps between the boulders on the South facing edge(sunny side). The plant puts down deep roots that mine the subsoil for nutrients that would otherwise leach away with the groundwater. The plant will spread very quickly, cutting back the spreading plants and dropping the material around the bed provides a source of these rescued nutrients to the other plants. 
Fragaria vesca – Wild Strawberry is planted on the edge of the sunny side for ease of picking and will over time provide a self-spreading ground cover throughout the bed suppressing weeds and protecting the topsoil from wind and rain erosion. 
Trifolium pratense -Red Clover is a nitrogen-fixing plant that can be planted on either side of the Blackcurrants – Ribes nigrum and in close proximity to the Fragaria vesca – Wild Strawberry. Cutting back this plant after you have used the flowers for a cup of tea will release some of the nitrogen fixed into the surrounding soil.
In the first season whilst your perennial plants establish you can plant annuals such as Tagetes patula or Centaurea cyanus to keep the ground covered. Both can also be used for teas.

 Chai Polyculture – August 2013 with annual Tagetes patula and T.erecta  added in the first season to fill space before the perennials grow.

Management

The plants in this polyculture will be competing for space both above ground and below ground. Above ground, we can position our plants in a way that fills the available space. Pruning back growth that may be interfering with a slower growing plant should be practiced as you see fit with the cut material applied to the soil surface as a mulch and harvested for teas. I usually combine pruning with harvesting.

In the spring a 3 or 4-cm thick application of well-rotted compost under the black currant and strawberry plants will ensure good fruit cropping. The windward side of the bed will act as leaf catchment in the autumn and raking up the leaves from the path and applying them to the surface of the soil will provide a good source of nutrients for the community.

Irrigating during dry periods will keep all the plants stress-free and in good health. Always water heavily and infrequently as opposed to lightly and frequently. A good soak every 10-14 days in the dry season will be more than sufficient.  As mentioned above the black currant and strawberries will benefit from watering when the fruit is setting.

Plants such as Mellisa officinalis -Lemon Balm, Spearmint – Mentha spicata,  Tansy – Tanacetum vulgare, and Achillea millefolium will spread via rhizomatous growth (underground horizontal stems). After a few years, these plants can be cut to ground level with the top growth applied to the surface then divided and moved to other areas around the garden or composted. You will need to hot compost the roots of these plants to ensure the destruction of the rhizomes. These plants provide a great diversity of mineral nutrients to your compost.  If you don’t have hot compost leaving the roots and stems of these plants in hot sun will destroy the rhizomes or soaking them in water for a few weeks and using the liquid as plant feed is another way of recycling the nutrients.

Planting

Harvest 

Some of the plants included in this polyculture are known to cause skin irritations and can have toxic effects if consumed in large quantities. Please be aware of any known hazards associated with every plant you consume. Caution aside we enjoy mixing and matching leaves and flowers from the plants in this guild to make phenomenal brews of healthy and invigorating teas and salads

Green Salad harvested in late April

Salads are best picked in the spring as the lush growth develops and in the autumn when the cooling temperatures and increased rainfall reinvigorate the plants.  Summer growth can be quite tough and bitter but a few leaves mixed with more tender greens provides great flavour and interest. Do not include leaves of Leonurus cardiaca – Motherwort in the salads. Please remember that although Ribes nigrum – Blackcurrant leaves can be used for tea other species in this genus such as Ribes rubrum – Redcurrants have leaves containing the toxin hydrogen cyanide.

As for medicinal value, all of these plants can be used to treat ailments but the best cure is prevention so get growing, get picking and drink up.

Habitat Provision

If you have an available source of rocks and boulders they make great bordering material. The gaps between and under the rocks provide excellent habitat for arthropods. Some of these, such as Woodlice and Millipedes function as decomposers, speeding up the return of nutrients to the soil. Some of these are generalist predators such as centipedes and spiders. These creatures seek refuge from the sun and heat in the cool damp microclimate under the stones. I often find Praying Mantis egg cases overwintering in a rock crevice protected from the rain but warmed by the winter sun. These egg cases can hatch hundreds of baby Mantids that have a voracious appetite for aphids. The rocks will also harbour creatures not so friendly to your plants such as slugs and snails and other phytophagous (plant-eating) organisms. In our garden, the frogs and toads seem to keep these under control.

Praying Mantis – Mantis religiosa egg case

Another benefit of using rocks is that being rocks they are laden with minerals that are released from the rock via chemical and physical weathering. These weathered minerals contribute to the soil’s stock. They can be thought of as the ultimate slow-release fertiliser.

The above-ground plant architecture itself also provides many habitats for many beneficial invertebrates to nest, feed, overwinter, hunt, and reproduce as will the mulch layer covering the topsoil.

Beneficial Insect Interactions and Flowering times

Not only do the plants provide us with fine teas, salads, and fruits they attract beneficial organisms such as ladybirds and hover-flies, and lacewings the larvae of which are efficient predators of aphids. Furthermore, a succession of nectar-bearing flowers keeps the bees and other pollinating invertebrates active and well-fed in your garden for most of the growing season where they can assist with the pollination of your surrounding fruit and vegetable crops. The table below provides information related to this.

 

Paul Alfrey

Hi I'm Paul, Originally from the UK I moved over to Bulgaria with my family 12 years ago and set up the Balkan Ecology Project. Prior to that, I worked as a freelance Arborist in the UK for 15 years. Balkan Ecology Project is a family project run by myself, Sophie and our two boys Dylan and Archie, and supported by the amazing volunteers we have hosted here over the years. We aim to develop and promote practices that provide nutritious affordable food while enhancing biodiversity and work to achieve this by: - Researching, designing and implementing systems on the ground - Providing working examples of our designs at our sites open for the public to visit - Providing quality education and training to aspiring growers and landscapers - Providing consultancy and design for landowners and farmers across Europe - Practicing an open source policy, whereby we disseminate our results freely and share all aspects of our work - Growing, selling and promoting the use of plants and plant communities that have high ecological and nutritional value Our activities currently include: Biological Plant Nursery, Educational Courses, Local Land Stewardship, Polyculture Research, Market Gardening​, and Consultancy and Design.

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