Joe’s Journal, Spring Edition: Companion Planting, Part II

Last time, we discussed different beneficial insects you will want to attract to your garden to help your landscape. This time, we will go over different plants and trees you’ll want to use to attract these insects.

Plants and Planning to Attract Beneficial Insects

Plant early, mid-season and late flowering species in your garden from the four groups discussed below. Planting a diversity of plants ensures a season-long “nectar flow” to support beneficials. The plants discussed in this post are grouped by their approximate time of flowering from spring to fall. Selecting a mix of species has additional advantages including:

• Ensures cross pollination for fruit set
• Supports a diverse community of beneficial insects
• Reduces the use of pesticides
• Supports the local ecology

Plants That Depend on Pollinators

So many of fruit bearing plants depending on pollination. These include tree fruits, berries and herbaceous plants grown for their fruit in the vegetable garden. Some of the more common plants include:

• Tree fruits:
  • Apples
  • Pears
  • Cherries
  • Peaches
  • Plums
  • Apricots
• Small berries:
  • Blackberries
  • Blueberries
  • Elderberries
  • Raspberries
  • Strawberries
  • Juneberries
• Fruiting vegetables:
  • Cucurbits (including cucumbers, melons, squash and pumpkins)
  • Solanaceae (including tomatoes, peppers and eggplants)

Reference 

Aromatic Herbs that Attract Beneficial Insects

In this section, we’ll describe plants in the families that attract beneficial insects. These include the Alliums, the Umbels, the Asters and the Mints.

The Alliums (Amaryllidaceae, formerly Alliaceae) produce compounds derived from cysteine sulfoxides (organosulfur compounds). Considered broad-spectrum natural insect repellents, they repel aphids, slugs, cabbage worms, Japanese beetle grubs and nematodes. They attract beneficial insects including bees, parasitic wasps, and hoverflies. They are good garden companions for roses and grapes, which are fed upon by aphids, Japanese beetles, and spotted lanternfly. The alliums deter rabbits and deer.

• Scallion – late winter to early spring
• Chives – mid spring to early summer
• Garlic – early to mid-June, the second year after planting
• Ornamental onion – late spring to early summer
• Garlic chives – late summer to early fall
• Onion – second year after planting
• Shallot – second year after planting
• Leeks – second year after planting

Reference 

The Umbels (Apiaceae /Umbelliferae) or Carrot family. This group forms a flower head in the shape of an umbrella. Most in the group are grown as an annual crop. Parsley, parsnip, caraway, carrot, angelica are biennials forming a rosette of leaves the first year of growth; in the second year, it forms a flower stalk. Lovage and fennel are perennial herbs. Of the group, the annuals will attract beneficials the first year planted. This family of herbs tend to form a taproot, so do not take well to transplanting. Sow seed directly and thin plants as they grow. Pre-soak the seed 24 hours ahead of time to help break seed dormancy. Make sowings every two weeks. Leave bolted plants in place to attract beneficial insects.

• Annuals that flower the same year planted:
  • Chervil – mid spring to early summer
  • Anise – late June to early fall
  • Coriander – late spring through summer
  • Cumin – mid-summer
  • Dill – midsummer to fall
• Umbels that flower in their second year:
  • Parsley
  • Parsnip – June to mid-July
  • Caraway – June to August
  • Carrot – June to August
  • Angelica – early summer
• Perennial Umbels:
  • Lovage – mid to late summer
  • Fennel – summer

Chervil (Anthriscus cerefolium) is a native to the Caucasus and widely naturalized in Europe. It is a cool season crop. Plant in spring and fall, as you would with lettuce. When the weather warms by mid-spring to early summer, the plants will bolt, forming a flower head.

Anise (Pimpinella anisum) is an Old-World plant first cultivated in Egypt and the Middle East, and later brought to Europe. Sow in spring as soon as the ground warms. It prefers well-drained soil rich in organic matter. It contains the essential oil anethole, which gives it its distinct flavor and scent.

Coriander (Coriandrum sativum) or Cilantro is a native to the Mediterranean region. It contains the essential oil linalool the major constituent of its aroma and flavor. It is a cool season crop that bolds in hot weather. The flower clusters are very attractive to syrphid (hover) flies and parasitic wasps.

Cumin (Cuminum cyminum) likely originated in Asia or the Mediterranean region. It is a tropical /sub-tropical crop and is vulnerable to frost. It grows best at temperatures between 77 and 86 F, and requires 120 days of frost-free weather.  Plant seed after all danger of frost has past, generally in mid- to late- May.

Dill (Anethum graveolens) is a native of North Africa and the Arabian Peninsula. It will bolt in hot weather. Sow after danger of frost has passed. Plant in full sun, in well-drained soil amended with organic matter. The plants are attractive to swallowtail butterfly larvae.

The Aster Family has flower heads most often comprise of numerous disc and ray (or strap) flowers. The rays resemble flower petals. The group is pollinated by insects and account for their attractiveness to beneficial insects. Select species with open centers (that is, flowers made up primarily of disc flowers), since these are more accessible to insect pollinators; single-flowering dahlias, marigolds, zinnias and chrysanthemums (rather than the double-flowering cultivars) are accessible to pollinators. Zinnia cultivars that attract butterflies include Zahara, Benarys’ Giant, Tall State Fair, California Giant, Cut and Come Again, and Lilliput. Korean chrysanthemums have open centers and flower in the fall, extending the season for pollinators. Some of the varieties available in the trade include: ‘Mary Stoker’ ‘Nell Gwynn’ and ‘Perry’s Peach’.

• Dandelions – early spring
• Dahlia – summer
• Marigolds – summer
• Zinnia – summer
• Sunflowers – summer /fall
• Purple Coneflower – summer /fall
• Cosmos – late summer /fall flowering
• Chrysanthemums – fall flowering
• Tansy – fall

Reference

Reference 2

The Mint Family (Labiatae /Lamiaceae) is a family of aromatic herbs, including the mints. Mints contain pulegone, an aromatic oil that repels mosquitoes and deters deer browse. Rosemary, thyme, lavender, sage, marjoram, and oregano are perennial sub-shrubs originating in the Mediterranean region. These mints prefer to grow in full sun in well-drained soils. Not all are winter hardy, and the least hardy ought to be grown as annuals. Among the most frost sensitive species are rosemary and marjoram.

• Rosemary – spring and summer
• Thyme – late spring /early summer
• Bee balm – June & July
• Mountain mint (Pycnanthemum muticus and flexuosum)– June through August
• Lavender – late spring to late summer
• Mint – July to August
• Sage – early summer
• Hyssop – late July
• Marjoram – summer
• Oregano – summer
• Savory – summer
• Winter savory – August to November

Rosemary (Salvia Rosmarinus) is an aromatic perennial evergreen shrub. It is drought tolerant. The flowers are blue, lavender or white. Flowering in spring into summer, it attracts bees, butterflies and hummingbirds. Its major drawback is that it is not winter hardy, doing best in zones 8 to 10. Rather than overwinter the plant indoors, which can be difficult, propagate by cuttings.

Reference

Reference 2

Garden Thyme (Thymus vulgaris) is a woody, broadleaf evergreen native to Europe an Italy. It prefers dry, sandy soils requiring good drainage. Plant in full sun. The flowers attract bees, butterflies, and other pollinating insects. Flowers spring and summer. It is winter hardy in USDA zones 5 – 9. Best propagated by cuttings.

Beebalm (Monarda didyma) is an aromatic herbaceous perennial plant, native to the North Carolina mountains. Plant in moist, well-drained soil in full sun. Beebalm attracts bumblebees, hummingbirds and swallowtail butterflies. It is intolerant of humid conditions and wet foliage as it is susceptible to powdery mildew and rust diseases.

Mountain mint (Pycnanthemum muticus) is a native aromatic perennial found in woodlands and thickets. It prefers moist to medium well-drained soils. It attracts pollinators in flower. Hardy from zone 4 to 8.

Appalachian Mountain Mint (P. flexuosum) is a native of North Carolina primarily found in the coastal and Piedmont areas of the state. Mountain mint prefers rich loamy soil, found naturally growing in alkaline soils, but it tolerates a range of soil pH. Plants can be divided for propagation. Flowers in late summer attracting pollinators including bees, butterflies and wasps. It is hardy in USDA zones 5 to 8.

English Lavender (Lavandula angustifolia) is an aromatic evergreen perennial sub-shrub native to the Mediterranean region. It requires well drained soil, and does not do well in heavy clay soils; it is susceptible to root rot. Lavender prefers a soil pH from neutral to alkaline. Propagate by stem cuttings. It blooms in summer and its blossoms attract pollinators. It is hardy in zones 5 to 9.

Peppermint (Mentha x piperata) is an aromatic herb, a cross between spearmint and water mint (M. aquatica). It is resistant to rabbit and deer browse, and can be invasive, spreading by rhizomes. Plant in a flower pot to contain; alternatively, plant along the edge of turf and mow to keep under control. Flowering in summer, it is attractive to pollinators.

Spearmint (Mentha spicata) is an aromatic herb native to Europe. It naturally grows in moist soils near ponds, lakes and fields. It spreads aggressively. Spearmint flowers summer to fall, and attracts bees and butterflies.

Garden Sage (Salvia officinalis) is an aromatic herbaceous (short-lived) perennial sub-shrub native to the Mediterranean region. The flowers are camphor scented bluish- or pinkish-lavender appearing in early summer attracting bees and butterflies. Plant in full sun in well-drained soil. It is intolerant of wet soil, but tolerates drought well. It is winter hardy in zones 4 to 8.

Anise Hyssop (Agastache Foeniculum) is an aromatic perennial herb. Plant in full sun to part shade in well-drained soil. Flowers in late July until late fall, and attracts bees, butterflies and birds. The plant will self-seed. It can also be propagated by division. Winter hardy in zones 5 to 9.

Marjoram (Origanum majorana), an aromatic sub-shrub that does best in well-drained soil in full sun. It prefers a neutral to alkaline soil pH. It is drought tolerant. However, it is not winter hardy: winter hardiness is limited to zones 9 to 10. Summer flowers attracts pollinators. Grow marjoram as an annual.

Oregano (Oreganum vulgare) is an aromatic woody perennial sub-shrub, native to the Mediterranean region. Flowering in summer, it attracts bees and butterflies. Plant in full sun in well-drained soil. Prefers a pH of 6.0 to 9.0 and a hot, dry climate. It is winter hardy in USDA zones 3 to 10.

Summer Savory (Satureja hortensis) is an aromatic annual herb grown from seed. It prefers full sun, well-drained soil rich in organic matter. It prefers an alkaline soil pH. A good companion plant as it repels insect pests. In flower, it attracts bees.

Winter Savory (Satureja montana) is an aromatic perennial herb. In habit, a sub-shrub. The plant is grown from cuttings or seed planted in early spring. It is a good companion plant for onions and beans and will repel insect pests. Plant it in well-drained soil, in full sun to part shade. In flower, it is attractive to bees and butterflies. Winter hardy in zones 5 to 10.

An Example of a Garden Plan

1. Plant bulbs of the ornamental (flowering) onion in the perennial border in fall
2. Sow seed of anise, chervil, coriander and dill in spring as soon as the soil can be worked
3. Sow seed (after danger of frost) of cosmos, and sunflowers in the flower garden
4. Sow seed (after danger of frost) of marigolds in the vegetable garden
5. Plant tubers of single flowering dahlia varieties in the flower garden
6. Set out rooted cuttings of sage, rosemary, thyme, and oregano after danger of frost

Planning and planting a diversity of pollinator plants in your garden beds will add color and interest throughout the growing season. Not only will you attract pollinators to help your trees, shrubs and vegetable plants be more abundantly fruitful, but you will have also helped to establish a diversity of predators and parasitoids to support the food web and by association, reduce the need to apply pesticides. This approach will give you more time to enjoy the fruits (and flowers) of your labor!

In our next blog, we’ll take a look at the new innovations in treating trees systemically for the control of destructive pests, methods that reduce unintended environmental impacts.

~ Signing off for now, Joe