A Companion is a Fine Thing

Stella D'Oro daylily and Walker's Low Catmint make fine companions.

A companion is a fine thing. Everyone needs a good companion. Even your garden plants!
Care must be taken to place plants where they can thrive and one important consideration is the companion plants who will share their space. Good companions enhance rather than detract from a community. Their positive influence causes plants to prosper, while a poor companion could sap energy creating an environment of mediocrity and impeded growth. It doesn’t need to complicated or stressful, but there are a few questions to ask when trying to select the right companions for your plant.

Morning glories grace the bridge. 

What does your plant need?

All plants need water, but some need a great deal more than others. Many gardeners group thirsty plants together close to the house or another water water source while placing low water plants together further away. Shade lovers would not be planted with sun lovers. Certain plants may need protection from wind or a certain kind of soil. It seems obvious that plants with similar needs might be good companions; these are first line considerations.

How does your plant behave?

Allium pokes its blooms through the boisterous spearmint.

While I hate to attribute poor behavior to any plant, who after all, only does what its genes tell it to do, still there are plants that seem to wake up each morning with world domination on their mind while others seem rather diminutive and shy. You’ll have to decide if the garden thugs even belong in your garden, especially if your are gardening in a small space, but for sure don’t place them next to that shy plant. You don’t even have to guess what will happen by the end of the season. My method, in a large country garden, is to plant my garden thugs together and let them duke it out. This might not work with dominating friends at a dinner party, but in a garden the result can be charming, if not slightly chaotic.

Are there color combinations that are especially pleasing to you?

Purple and white coneflower combine well with a salmon daylily and sea lavender.

There are no rules here. Some gardeners are very precise in their color selection, preferring to place pastel or vivid hues together. Others enjoy a monochrome garden choosing just one color, often white, to be the sole color (other than green, of course). The variations are endless and personal.

The highlight of summer are the daylily blooms. 

When is the plant in peak form (blooming or harvesting)?

The joy of annuals is that they often bloom throughout the entire season. In the vegetable garden, nearly all the plants would be considered annuals meaning that they complete their life cycle in one year although the peak harvest could be in early spring for one plant (such as peas) and late fall (such as sweet potatoes) for another. The joy of perennials is that they return year after year. However, they usually have a shorter bloom time. Is it better in a perennial flower garden to have blooms sprinkled throughout the garden all season or grouped together leaving areas with little bloom during certain times? My vote goes with the grouping giving splashes of impact during each part of the season. In the vegetable garden, the opposite may be true. It may be efficient use of space to place late season crops next to early season crops. As the early season crops are harvested and spent plants are removed, late season crops can take over. You may wish to consider this with land-hungry vining plants such as pumpkins or cucumbers.

The slender stem of allium allow placement anywhere.

How does the plant interact with other plants?

You know how some people just don’t do each other any good, while others push each other to be better? It’s the same with plants. While few are downright toxic to plant growth (although the black walnut tree is) some are much better companions than others. Studies, observations and ancient wisdom tell us that this is so. Plants may assist other plants by adding nutrients to the soil (legumes are well known for fixing nitrogen), attracting beneficial insects or repelling harmful pests. Some plants just seem to help each other out for no discernable reason. Others make good companions, not because they help each other in any discernable way, but because they don’t compete for the same nutrients.

Many people look to the “Three Sisters” as an example of native American tradition which combines corn, beans and squash (often pumpkin). Corn provides support for vining beans, beans add nitrogen to the soil and squash leaves shade out encroaching weeds. In many vegetable gardens across America you’ll find marigold flowers interspersed with the vegetables because marigolds are thought to repel pests.

Old-fashioned phlox bloom vigorously beside a lovely hibiscus shrub.

Perhaps the best companion for the garden is the gardener. The careful eye, the gentle cultivation, the pause to admire, the delight in harvest can bring out the best in your plants.