Home Gardening Center at THE NEW YORK BOTANICAL GARDEN________________________________________________________________________ Companion Planting for RosesBy Sonia Uyterhoeven What makes a good companion?Plants, like people, are searching for partners that will make them look good; bring out their bestqualities, and share their space with equanimity — neither overpowering nor paling incomparison.There are several considerations when choosing suitable plant companions: aesthetics, growingconditions, and plant health. Plant companions should both look good together and requiresimilar growing conditions. Another component of companion planting, one often referred to inorganic gardening, is selecting companions that ward off pests, improve the soil, or in otherways have a beneficial effect on plant health.Texture, color, and form are all important in the aesthetics of companion planting. Plants withtall spires complement the wide, cup-shaped flowers of roses, while perennials and shrubs withpale green, silver, or purple leaves accentuate the sumptuous rose blossoms. Companionplanting can also extend the flowering season by providing color between the main flushes ofrose bloom in early summer and fall.Some plants just seem to be made for each other. The feathery purple and blue-gray catmint(Nepeta) offsets any pale pink rose beautifully, and its wispy spires gracefully camouflage anyblemishes that may occur on the rose’s foliage. While the tops of roses are nice and lush, thebottoms can become leggy and sparse. Good companions are those that hide their bare legs.Traditionally, lavender (Lavandula), catmint (Nepeta), lady’s mantle (Alchemilla), and tallgrowing pinks (Dianthus) all make good partners. Good companions also act as livingmulches—suppressing weeds and lightly shading the soil, keeping their roots nice and cool.Good companions should enjoy the same growing conditions but not compete too aggressivelywith 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 take too much water and nutrients fromthe soil.Many sun-loving annuals such as heliotropes (Heliotropium), summer-snapdragon (Angelonia),lantana (Lantana), and verbena (Verbena) hold up well throughout the summer and fill thespace among roses nicely. They all have modest water requirements and will benefit from theheavy feeding regime that roses demand.Good companions are said to enhance one another’s growth or, in some way, protect eachother from harm. Some companion plants may help discourage pests without the use ofchemicals since there are natural substances in their leaves, flowers, or roots that repel insects.Roses love garlic is a popular expression. In fact, members of the onion family such as chives,ornamental alliums, and edible onions, are rumored to increase the perfume of roses, ward offaphids, and prevent black spot.Herbs and other aromatic plants make wonderful rose companions. Scented geraniums(Pelargonium), rue (Ruta), feverfew (Tanacetum), parsley (Petroselinum), and thyme (Thymus)
all may help ward off Japanese beetles and aphids. Marigolds (Tagetes) may also repel pestsand encourage growth. Try ornamental and culinary sage (Salvia), anise-hyssop (Agastache),Russian-sage (Perovskia), lavender (Lavandula), yarrow (Achillea), oregano (Origanum),catmint (Nepeta) and calamint (Calamintha). Oddly enough, tomatoes allegedly prevent blackspot, but not many people will be inclined to combine roses and tomatoes. Lavender(Lavandula) and catmint (Nepeta) are good at keeping rabbits away. Four-o’ clocks (Mirabilis)and larkspur (Consolida) are said to act as decoys by attracting rose-loving Japanese beetles toeat their poisonous leaves. Yarrow (Achillea) may attract ladybugs who in turn feed on aphids.Remember to plant companions at least one foot away from your roses so that you do notdisturb their roots. 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 anddiseases. With proper care of your roses, you will be able to surround them with manyinteresting companions. Here a just a few suggestions:Good Plant Partners:Perennials ShrubsAnise-hyssop (Agastache) Blue mist shrub (Caryopteris)Bellflower (Campanula) Boxwood (Buxus)Catmint (Nepeta) Daphnes (Daphne)Blue false-indigo (Baptisia) Red-twig dogwood (Cornus)Garden phlox (Phlox) Smokebush (Cotinus)Globe thistle (Echinops) Spirea (Spiraea)Geraniums (Geranium)Germander (Teucrium) AnnualsLady’s mantle (Alchemilla) Annual phlox (Phlox)Lavender (Lavandula) Four o’clock (Mirabilis)Lilies (Lilium) Heliotrope or cherry pie (Heliotropium)Meadow sage (Salvia) Lantana (Lantana)Ornamental onions (Allium) Larkspur (Consolida)Red hot poker plant (Kniphofia) Million bells (Calibrachoa)Russian-sage (Perovskia) Pansies (Viola)Sea-holly (Eryngium) Persian shield (Strobilanthes)Spurge (Euphorbia) Summer snapdragon (Angelonia)Wormwood (Artemisia) Flowering tobacco (Nicotiana)Yarrow (Achillea) Verbena (Verbena) Visit Home Gardening Online at nybg.org Generous support for the Home Gardening Center has been provided by Kenneth and Ellen Roman.