Some plants appear to have a direct effect on others growing near them. In some cases the effect is beneficial, while in others it is detrimental.
Roses, for example, seem to be more sweetly scented and less prone to disease when surrounded by garlic, and less troubled by aphids when lavender is grown underneath them.
But beans do not seem to do well when grown near onions.
Mixed planting benefits
Plants of different species, when grown together, compete less with each other than those of the same species, and make it more difficult for pests and diseases to spread. For example, planting potatoes and broad beans together can increase the yields from both crops.
Flowers that attract pollinating insects can increase the yields from some other crops. Sweet peas and runner beans work as good companions in this way, and also look very attractive scrambling up bean poles together in flower and vegetable gardens.
Other winning combinations include:
- tomatoes and cabbage
- cucumbers and nasturtiums
- rosemary and sage
- French marigolds and pretty much everything
Cabbages and tomatoes make a good team in the vegie patch
Weed beaters
Few weeds grow in pine woods because secretions from the trees prevent them from germinating. A mulch of pine needles on the strawberry bed will suppress weeds and may also improve the fruits’ flavour.
Rhododendron leaves produce secretions that prevent seeds in the soil nearby from germinating, and the leaves of dandelions appear to have the same effect.
Space savers
Make good use of space in the vegetable garden by planting shallow-rooting vegetables alongside deep-rooting ones. Carrots and radishes do well together and occupy less space when planted side by side than when planted in separate rows.
Disease resistance
Some plants can increase the ability of others to resist disease:
- Chamomile is beneficial to the health and fragrance of certain plants
- Foxgloves and golden feverfew (Tanacetum parthenium ‘Aureum’) are helpful to plants nearby
- Summer savory benefits beans
- Onions can prevent mould on strawberries