Plants, like people, do best with partners that will bring out their top qualities and share their space with equanimity, neither overpowering nor paling in comparison. There are several considerations when choosing suitable plant companions: aesthetics, growing conditions, and plant health. Plant companions should both look good together and require similar growing conditions. Another component of companion planting, often referred to in organic gardening, is selecting companions that ward off pests, improve the soil, or have a beneficial effect on plant health in other ways.
A great resource recommended on this subject is Jackson & Perkins Rose Companions: Growing Annuals, Perennials, Bulbs, Shrubs, and Vines with Roses, by Stephen Scanniello. Formerly a rose curator at the Brooklyn Botanic Garden, Scanniello offers expert advice on how to create a stunning garden with roses and companions plants, or, as he states in the introduction, “how to get roses to play well with others."
Plants That Look Good With Roses
Texture, color, and form are all important in the aesthetics of companion planting. Plants with tall spires complement the wide, cup-shaped flowers of roses, while perennials and shrubs with pale green, silver, or purple leaves accentuate the sumptuous rose blossoms. Companion planting can also extend the flowering season by providing color between the main flushes of rose bloom in early summer and fall.
Plants That Solve Problems for Roses
Some plants just seem to be made for each other. The feathery purple and blue-gray catmint (Nepeta) beautifully offsets a pale pink rose, and its wispy spires gracefully camouflage any blemishes that may occur on the rose’s foliage.
While the tops of roses are nice and lush, the bottoms can become leggy and sparse. Good rose companions are those that hide their bare legs. Traditionally, lavender (Lavandula), catmint (Nepeta), and tall growing pinks (Dianthus) all make good partners. Good companions also act as living mulches—suppressing weeds and lightly shading the soil, keeping rose roots nice and cool.
Plants That Enjoy the Same Conditions as Roses
Ideal rose companions enjoy the same growing conditions but do not compete too aggressively with the roses. Roses do best in full sun and well-drained soil, and so should their companions. Plants that are too aggressive may crowd the roses and absorb too much water and nutrients from the soil.
Many sun-loving annuals, such as heliotropes (Heliotropium), summer-snapdragon (Angelonia), lantana (Lantana), verbena (Verbena) and million bells petunia (Calibrachoa), hold up well throughout the summer and fill the space among roses nicely. They all have modest water requirements and will benefit from the heavy feeding regime that roses demand.
Plants That Discourage Pests
Good companions are said to enhance one another's growth or protect each other from harm in some way. Some companion plants may help discourage pests without the use of chemicals because there are natural substances in their leaves, flowers, or roots that repel insects.
Roses love garlic. In fact, members of the onion family, such as chives, ornamental alliums, and edible onions, increase the perfume of roses, ward off aphids, and prevent black spot.
Herbs and other aromatic plants make wonderful rose companions and all may help ward off Japanese beetles and aphids. including:
Tomatoes allegedly prevent black spot, though not many people are inclined to combine roses and tomatoes. Lavender and catmint are good at keeping rabbits away. Four o’clocks (Mirabilis) and larkspur (Consolida) act as decoys by attracting rose-loving Japanese beetles to eat their poisonous leaves. Yarrow attracts ladybugs who in turn feed on aphids.
How to Plant Rose Companions
Remember to plant rose companions at least 1 foot away from your roses so that you do not disturb their roots. Leather gauntlet gloves might come in handy when working in your rose garden. Thorn-resistant kidskin leather molds to your hands and stress points at thumb and fingertips are reinforced for long-lasting wear.
Create a healthy open structure for your roses with good pruning practices. Always maintain good air circulation around your plants to help prevent attacks from pests and diseases. With proper care of your roses, you will be able to surround them with many interesting companions.