Companion Planting – Using Flowers
Hospitable Habitat
One of the most important aspects of the companion planting theory is attracting beneficial insects to the garden…and, more importantly, keeping them there. All living beings require food, water and shelter to survive. Aside from the obvious meal (garden pests,) beneficials love the pollen and nectar provided by a diverse array of vegetables, herbs, and flowers.
So, a few points to consider when choosing and placing flowers in the vegetable garden.
*Having an abundance of flowers among your vegetables serving different functions as companion plants is confusing to pests. That’s exactly what you want!
*When choosing varieties, note that a single ring of petals like you see in a daisy, are better that those with dense multi-layered petals because they have more nectar that is easy to get to by the beneficial insects.
*Consider organizing your flower choices by bloom times ensuring that you will have companions flowering throughout the vegetable growing season.
*Adding flowers that serve as trap crops as one of their companion functions is a great benefit. Placement of a trap crop is important to understand, too. For some insects, it is sufficient to plant a trap crop around the borders of the garden. Others are harder to stop and require inter-planting them to draw them off of the main crop you are trying to protect. Aphids, for example, love nasturtiums and calendula. Inter-planting them with a crop that gets aphids, like broccoli, can save the vegetable. When a trap crop becomes overrun with a pest, you can remove it or thin it out.
There are many, many flowers that are good companions for the vegetable garden, but I’ve narrowed it to 18 easy to grow annuals and perennials.
The best place to start is to compile their benefits in an easy to read chart showing bloom time, size, good ones to use as inter-cropping in the same container as the vegetable, and which are trap crops. ALL of the flowers are going to draw in beneficials, but the ones I’ve chosen have multi-functions.
Alyssum –Annual, but some are hardy in frost-free climates. Most varieties will fade in the heat but bloom again in the fall. (It is a delicate carpet of tiny flowers with a subtle, sweet scent. The low-growing foliage is covered by flowers for much of the growing season. Sweet alyssum is a very good choice to add to containers filled with taller plants.)
Benefits:
- Attracts lacewings, parasitic wasps, tachinid flies, hoverflies and butterflies.
Companion Plants:
Plant near: anything
Foes:
Found none in my research.
Seed Starting:
Very easy to grow from plant or from seed. It is a cool season flower that can be set out in early spring. Transplants or sow seeds indoors 4-5 weeks before last frost. Transplant out after last frost. Or direct seed as soon as the soil can be worked.
Alyssum likes rich, loamy soil. Sow seeds on surface of potting mix. They require light to germinate. Thin when seedlings have first true leaves. Seedlings emerge in 8-10 days at 65-70 degrees F.
Height: 4-6” tall, Spread 6-9”, Blooms early spring/summer and early fall, grows in Full Sun to partial shade. Hardiness Zones: 7-11
Maintenance:
Flowering may slow in August. Give it a haircut when the stems get leggy removing ½ of the growth. This will promote flowering again once night temperatures cool off.
Astrantia –Perennial. (This hardy, wild plant is usually grown in cottage gardens. Astrantia has bushy, large dark green foliage and small inflorescences in shades of red and pink, which remain on the plant from summer to fall. Prefers to be planted in part shade to full shade and continuously needs evenly moist soil. It is usually grown on the ground, but is very possible to thrive in pots too.)
Benefits:
- Attracts beneficial insects
- Perennial
Companion Plants:
Plant near: anything
Foes:
Found none in my research.
Seed Starting:
Sow seeds in the fall or early spring or by division. Surface sow seeds on the ground, in a container, or in growing trays after having placed the seeds in the refrigerator for 6 weeks as they require cold stratification to germinate. Optimum seed germination is around 60 degrees F.
Height: 2-3’ tall, Spread 18-24”, Blooms spring to fall depending more on the climate, grows in Partial Shade to Full Shade. Hardiness Zones: 4-9.
Maintenance:
Keep the plant mulched to help retain moisture. Deadheading will encourage the plant to flower more. If you want to collect seeds or multiply them, leave some blooms at the end of the season and let them seed. Feed in spring with a balanced, liquid fertilizer.
Bee Balm –Perennial, also known as wild bergamot. (A classic American native and cottage garden favorite beloved not only for its beautiful whorled blooms in red, pink, purple, and white; but for the evocative fragrance given off by the foliage warmed by the sun or touched by the gardener. It prefers evenly moist soil rich in organic matter, so container planting with a saucer underneath to hold a bit of water is good. Choose dwarf varieties for containers.)
Benefits:
- Lures nectar sippers ensuring good fruit set. Loved by bees and hummingbirds in the summer and by seed-loving finches in the winter.
Companion Plants:
Plant near: anything
Foes:
Found none in my research.
Seed Starting:
Available to plant in the spring and fall. However, when planting in the fall, it is best to trim back the foliage to encourage the plant to focus its energy towards the roots. Transplants or sow seeds indoors. Surface sow the seeds 5-8 weeks before last frost date and keep under light. Bee Balm needs light to germinate, Seedlings emerge in 14-21 days when kept at 60-70 degrees F.
Height: Dwarf varieties 15” tall, Spread: 18-24”, Blooms early spring/summer and early fall, grows best in Full Sun. Hardiness Zones: 3-9.
Maintenance:
Deadhead faded blooms to encourage re-bloom in late summer. After first frost in the fall, cut stems to 2”; divide every 2-3 years in the spring.
Calendula –Annual, often called “pot marigold” but, actually, is a member of the daisy family. There are 20 species of calendula. It gets its name from a Latin word meaning “little calendar,” mainly due to its promptness in blossoming at the beginning of the month. (Calendula can be inter-planted with crops or in its own container. It does not like wet feet.)
Benefits:
- Attracts bees, hoverflies and ladybugs.
- Deters Japanese beetles and tomato hornworms.
- Exudes a sticky substance on the stems that attracts aphids and traps them there.
Companion Plants:
Plant near: anywhere, tomatoes, asparagus, anywhere, but good with crops that attract aphids such as broccoli
Foes:
Found none in my research.
Seed Starting:
The bizarre looking seeds can be direct sown or seed started indoors. They are easy to germinate, fast growing, reseeds. Start plants indoors 6-8 weeks prior to last frost date. Plant ¼” deep, keeping the potting mix moist, but not wet. When starting indoors, maintain darkness until germination occurs and then supply bright light to keep seedlings compact. Thin out seedlings and plant 12” apart or they will be stunted. Calendula blooms 45-60 days after germination.
Height: 12-30” tall, Spread: 12-18”, Blooms early summer to fall, grows in Full Sun to Partial Shade. Hardiness Zones 2-10.
Maintenance:
Pick flowers every two days. Feed every two weeks. Pinch back to encourage bushiness. Avoid overhead watering as plants are susceptible to mildew. Deadhead regularly to prevent self-sowing.
Cosmos –Annual, with colorful 3-5” daisy-like flowers in various colors, including pink, orange, red and yellow, white and maroon that sit atop long slender stems. Cosmos make great cut flowers and will do well in containers, too. It is very drought tolerant.)
Benefits:
- Attracts bees, birds, and butterflies.
Companion Plants:
Plant near: anything
Foes:
Found none in my research.
Seed Starting:
If growing from seed, note that it takes 7 weeks to first bloom. After that, your flowers should continue to bloom until the next frost. Seed start 4-6 weeks prior to last frost date. Move them into 5” pots as soon as they are 3-4” tall.
Height: 18-60” tall depending on variety. Blooms early summer to fall, grows in Full Sun to partial shade. Hardiness Zones 2-10.
Maintenance:
If you let the spiky-brown seed heads blow away during the fall, cosmos might self-sow throughout your garden. Deadhead fading blooms.
Chrysanthemums –Perennial, often called hardy mums. (To be perennials, mums must be planted in the spring to early summer to have time to settle in and will return in subsequent seasons.)
Benefits:
- Repels roaches, ants, Japanese beetles, ticks, silverfish, lice, fleas, bedbugs, spider mites, harlequin bugs and root-knot nematodes.
- The ingredient in mums that make it so effective against pests is pyrethrum, which in used in pesticides.
Companion Plants:
Plant near: anything
Foes:
Found none in my research.
Seed Starting:
It’s best to buy transplants. Mums need cold to initiate their flower buds.
Height: 1-3’ tall, Spread 1-3.’ Blooms late summer and fall for 4-6 weeks depending on the cultivar, its location and its growing conditions. Grows in Full Sun. Hardiness Zones 4-9.
Maintenance:
You can divide mums in early spring when you first see new growth.
Daisy –Perennial, there are numerous varieties of this classic, cheerful flower. The daisy may not appear stunning, but the single ring of petals (more nectar,) makes parasitic wasps and hoverflies love them. (Daisy should be planted in its own container. It does not like wet feet.)
Benefits:
- The composite flowers attract a wide range of beneficial insects.
Companion Plants:
Plant near: anything
Foes:
Found none in my research.
Seed Starting:
Daisies can be seed started, but know that they bloom the second year. So, if you want blooms immediately, purchase transplants. Daisies are self-sowers.
Height: 2-3’ tall, Spread: 1-2’ wide clump. Blooms early summer to fall, grows in Full Sun. Perennial for zones 9 and up. Annual for colder climates.
Maintenance:
Water in the summer only if rainfall is less than 1 inch per week. After the first killing frost, cut stems back to an inch or two above the soil line. Every spring, apply some compost. Every 3-4 years, divide again in early spring or late summer.
Tall species and cultivars require support. Bamboo stakes are a good choice for any plant that has a strong, single stem and needs support.
Echinacea –Perennial in zones 3-8 and native to North America, commonly known as coneflower which comes from its cone-shaped central disc that stands out prominently among the single layer of slightly reflexed or droopy petals. (Echinacea should be planted in its own container; there are newer cultivars especially good for pots. They do not like wet feet.)
Benefits:
- Attracts butterflies and bees.
- Long blooming season that stretches into fall.
- The central disc florets produce plenty of nectar.
- The dried up flower heads are a goldfinch magnet in fall and winter.
Companion Plants:
Plant near: anything
Foes:
Found none in my research.
Seed Starting:
Can grow from seeds, divisions, and root cuttings, but if growing from seed, cold stratification is required. You can either sow the seeds out in the garden or in containers in late fall, and allow winter to provide the dormancy the seeds require before germination or by placing seeds in damp paper towels inside a closed plastic bag and storing them in a box in the refrigerator for 6-8 weeks. Transplant seedlings in the spring.
Height and Spread: Variety dependent. Grows in Full Sun, can tolerate some shade but won’t be as prolific a bloomer. Perennial for zones 3-8. Annual for warmer climates.
Maintenance:
It self-seeds readily, so remove seed pods if you don’t desire it to do that. Deadheading is the main task to extend the summer blooming season well into fall and to prevent uncontrolled self-seeding all around the garden.
Geraniums –Annual; Perennial in zones 10-11. Geraniums are very adaptable to being planted either in the garden or in containers. They are popular for their bright and sometimes fragrant flowers, but they bring with them the extra bonus of being good companion plants. (They do not like wet feet.)
Benefits:
- Odor discourages beetles, spider mites, leafhoppers, earworms, cabbage worms and cotton aphids.
- Trap crop for Japanese beetles (24 hour paralyzation for the chewers.)
- Attracts beneficials.
Companion Plants:
Plant near: anything, roses, grapes, raspberries, fruit trees
Foes:
Found none in my research.
Seed Starting:
You can grow from seed or cuttings or transplants. Key to starting from seed is to start very early; it takes 12-16 weeks to get flowering plants.
They need nighttime temps between 50-60 degrees F to bloom, so they are early summer and late autumn bloomers depending on your climate.
Height: 6-12”, Spread: 1’. Grows in Full. Perennial for Zones 10-11. Annual for colder climates.
Maintenance:
Allow to dry out between waterings. Prune out stems from center of the plant for air circulation. Deadhead spent flowers and pinch stems to promote bushiness and discourage legginess. Feed liquid high phosphate fertilizer at half-strength every 2-3 weeks.
Marigolds –Annual, probably the most well-known plant for repelling insects. There are many claims about marigolds and their benefit to the vegetable gardens, however, a little more detailed information might be beneficial here. It is the wild Mexican marigold, Tagetes minuta, that repels soil nematodes, although cultivated varieties, such as T. patula and T. erecta, are less effective. The rule seems to be: The more highly bred and less odoriferous the marigold, the less effective it is as a pest deterrent. Some hybrid marigolds, in fact, may stunt the grown of nearby plants and attract pests such as spider mites and snails. The wild marigold doesn’t look at all, like the marigolds we are used to seeing and blooms in late summer/fall. Having said that, there are some Mexican marigolds (also called French marigolds,) that are said to have benefits. (The marigold does not like wet feet.)
Benefits:
- Various types are said to repel a vast number of pests such as aphids, potato bugs, squash bugs, white flies, bean beetles, maggots, mosquitos and rabbits.
- The wild Mexican marigold’s roots repel nematodes but that requires a year to take effect.
- Said to potentially spur the growth of plants, especially roses.
Companion Plants:
Plant near: brassicas, cucurbits, peppers, tomatoes, eggplant, squash, kale, basil, all garden crops
Foes:
Found none in my research.
Seed Starting:
Marigolds are easy to seed start outdoors. In order for marigolds to be ready for planting outdoors in the spring, you will need to start seeds 50-60 days before the last frost date. Seeds germinate best with some warmth. Height and Spread: Variety dependent. Perennials in Zones: 9-11.
Maintenance:
If planted in-ground, only water if weather has been very dry for more than two weeks. If in containers, check daily as containers may dry out more quickly. Deadheading will increase the number of blooms and the blooming time length.
Nasturtiums – Annual; nasturtiums are the poster child of companion planting. If you’ve never tried these in the vegetable garden, I urge you to give it a go! (They are a self-seeder and are on the invasive list in CA. They can be planted in their own containers or 1 small mounding variety in with a vegetable.)
Benefits:
- They release a chemical that repels predacious insects protecting not just them, but other plants in the grouping while not repelling pollinators. Repels white flies, squash bugs, spiders, many beetles and cabbage loopers.
- They are a trap crop for aphids. Planting with or near beans, a vegetable that aphids like, will draw the aphids away. When the aphids load up on the nasturtiums, you can then remove the infected stems or the whole plant.
Companion Plants:
Plant near: anything, tomatoes, cucumbers, beans, kale, kohlrabi, collards, broccoli, apple trees, potatoes, pumpkins, cabbage, radishes
Foes:
Found none in my research.
Seed Starting:
The hard outer shell benefits from scarifying and soaking for 24 hours. Sow seeds in spring once all danger of frost is over or start early indoors 3 weeks before last frost date. Takes 9-12 days to germinate.
Height: Varies by type, but generally, 9-12”, Spread: 9-12.” Grows in Full Sun to Partial Shade in hot, humid climates
Maintenance:
Nasturtiums will grow and flower readily with no added fertilizer in most soils. They benefit from deadheading and pinching back if stems get leggy.
Penstemons –Perennial, newer varieties that are shorter and will flower the first year are perfect for container planting. (They do not like overly wet soil.)
Benefits:
- Attracts hummingbirds
- Deer resistant
Companion Plants:
Plant near: anything
Foes:
Found none in my research.
Seed Starting:
Sow Feb-March indoors, May to August outdoors. Lightly cover seeds…they should be visible through the soil. 2-3 seeds per plant, 12 inches apart. As with all seed germination, keep soil moist not soggy wet. It should not dry out, not even once or seeds will not grow. Moderate water after seeds have sprouted. Germination time 14-30 days. Penstemons will thrive in any type of soil but requires good drainage. Blooms early spring to first frost.
Height: 30” average, Spread: 8-12” wide clump. Grows in Full Sun to Partial Shade. Perennial for Zones 7-10. Annual for colder climates.
Maintenance:
Don’t cut back penstemons in autumn because they are slightly tender. Always leave the foliage intact until April, only cutting back the leaves to the lowest shoots when spring is well and truly here. They will self-seed.
Petunias –Annual; Perennial in zones 9-11. Petunias are nature’s version of a pesticide! (Some varieties are more suited to container growing. They do not like overly wet soil.)
Benefits:
- Repels: some types of aphids, tomato hornworms, asparagus beetles, leaf hoppers, Mexican bean beetles, and squash bugs.
- Said to enhance the growth of tomatoes, brassicas, beans, basil, grapes, and peppers.
- Scent attracts bees, butterflies and beneficial moths.
- Tolerates lots of heat and relatively undemanding when it comes to water.
Companion Plants:
Plant near: anything, beans, tomatoes, peppers, basil
Foes:
Found none in my research.
Seed Starting:
You can grow from seed, but it is easier to grow them from transplants. If you grow from seeds, start them indoors 10-12 weeks before last frost date. The seeds are very small and need lots of light to germinate. Add a balanced fertilizer when potting out in the garden. Wait until soil warms and frost danger has passed before transplanting outside.
Height: 12-15”, Spread: 1’. Grows in Full Sun to Partial Shade (fewer flowers in shade.) Perennial for Zones 9-11. Annual for colder climates.
Maintenance:
Require little maintenance, but benefits from liquid fertilizer every 3 weeks starting mid-summer. Remove faded flowers including the portion below each flower where seeds will develop. Deadheading not only helps prolong blooming, it also keeps plants looking fresh, healthy and well-groomed.
Phacelia –Perennial if left to reseed. Overwinters well. (Expect phacelia to be abuzz with bumblebees in the early spring.)
Benefits:
- Flowers provide nectar for bees and other beneficials early spring.
Companion Plants:
Plant near: anything, cucumbers, tomato, kale, broccoli, and cabbage
Foes:
Found none in my research.
Seed Starting:
Sow in spring while the soil is still cool. Make sure seed is well covered as the seeds need darkness to germinate. Sow ¼” deep. Thin to 10” apart in all directions.
Height: 9”, Spread: 9”. Grows in Full Sun to partial afternoon shade. Hardiness Zones 3-10.
Maintenance:
Can be pulled up and composted or turned under anytime. Pull up individual plants grown for flowers before they shed seeds just after it blooms, but before it develops mature seeds. Wear gloves when handling as it can cause skin irritations for some people.
Poached Egg Plant –Annual, Perennial if left to reseed. It’s name comes from the flower, a bright yellow low center surrounded with white petals which looks like a poached egg. (Can be planted in its own container or mixed with other vegetables, flowers, or herbs. They like moist soil.)
Benefits:
- Attracts: bees, hoverflies, lacewings, and ladybirds
Companion Plants:
Plant near: anything, fruit trees, beans, lettuce, tomatoes
Foes:
Found none in my research.
Seed Starting:
Sow in ground or in containers early spring when the soil is cool; sow seeds ½” deep and thin to 4” apart in all directions. Needs a balanced organic potting mix.
This low-growing plant spreads into a mat of green foliage covered with flowers from June to September.
Height: 6-12”, Spread: 6-9”. Grows in Full Sun to partial afternoon shade.
Maintenance:
Pull up old plants to limit reseeding.
Sweet Peas –Two Types: Annual, and everlasting Perennial varieties that are much less fragrant. Sweet Peas are one of the most popular cottage garden flowers and are great as cut flowers. The more you cut, the more you get! (They are climbers and need an arch, trellis or some support structure. Plant in ground or in pots.)
Benefits:
- Emit a lovely fragrance.
Companion Plants:
Plant near: anything
Foes:
Found none in my research.
Seed Starting:
Sweet Pea seeds are easy to grow. You can sow them into pots of compost in autumn and overwinter in a cold frame or cool greenhouse. Or you can wait until spring when you can sow in pots or directly into the ground. Soak the seeds overnight so they will swell with moisture. Use a good quality composted potting soil or add compost to the ground. Sow seeds ¼” deep. You can also buy sweet pea transplants. As the seedlings grow, they’ll start to become tall and leggy. Encourage them to produce side shoots by pinching out the tops of the plant. Simply nip off the top of the stem with your fingers, just above a set of leaves. This will make each plant bushier and more robust, and the more shoots, the more flowers.
Plant out seedlings in April, or once your sweet peas are growing well and the main risk of frost has passed. Place 2-3 sweet peas in each hole for a nice, full display. Aim to plant each group about 5-6” apart. Slugs love the tender seedlings so put out slug traps like beer in a bowl, slug-O, etc. while they are young and growing. Height: 6-8’ Hardiness Zones: 1-13. Plant in Full Sun.
Maintenance:
Help the tendrils to attach to the trellis by tying as they grow. Do this every 7-10 days. Keep them well-watered as dry soil makes them go to seed quicker. Deadhead them regularly to encourage more blooms.
Sunflowers –Annual, say SUMMER like no other plant. (They do not like overly wet soil.)
Benefits:
- Attracts bees, birds, and butterflies.
- Heat tolerant, resistant to pests, and beautiful.
Companion Plants:
Plant near: near cucumber
Foes:
Potatoes and sage
Seed Starting:
Sow directly outdoors after the danger of spring frost is past. Sow 1” deep, 6” apart. Give plants plenty of room, especially for low-growing varieties that will branch out. They are heavy feeders, so plant in their own containers. Height: Variety dependent. Grows in Full Sun. Hardiness Zones: 3-10
Maintenance:
Feed plants only sparingly, over-fertilization can cause stems to break in the fall. Tall species and cultivars require support. Bamboo stakes are a good choice for any plant that has a strong, single stem and needs support.
Zinnias –Annual, easy to grow and make a massive burst of color in your garden. (They do not like overly wet soil.)
Benefits:
- Great nectar source for pollinators.
Companion Plants:
Plant near: anything, zucchini, chard, and dwarf beans
Foes:
Found none in my research.
Seed Starting:
Zinnias should be grown from seed in the garden as they do not like to be transplanted as nursery plants and do not often thrive. From seed, they will grow very quickly in the right conditions: wait until after the last frost has passed, plant in full sun, Daytime temps – can stand a minimum of 60 degrees F but prefer a range between 74-84 F, prefer fertile, humus-rich soil and well-draining soil.
Sow seeds ¼” deep. Many varieties are planted 6” apart. Most germinate in 4-7 days. When seedlings reach 3” tall, thin them so that they’re 6-18” apart to maximize air circulation. Height: Variety dependent, Spread: 4-24” depending on variety. Grows in Full Sun.
Maintenance:
Deadhead to prolong flowering. Maintain moderate soil moisture and fertilize lightly. Sow in succession for a longer flowering display. They will die with the first fall frost.
“There is a language, little known,
Lovers claim it as their own.
Its symbols smile upon the land,
Wrought by nature’s wondrous hand;
And in their silent beauty speak,
Of life and joy, to those who seek
For Love Divine and sunny hours
In the language of the flowers.”
-The Language of Flowers, London, 1875
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