Plant these for anti-ant landsscaping

When it comes to ants, humans are outnumbered by about 2.5 million to one. With more than 15-thousand species almost everywhere on earth, ants are eventually bound to show up in a place where you don't want them, from your home to your prized plants.

The key to deterring ants naturally with plants relies primarily on scent. These insects have four to five times as many scent receptors in their antennae as other insects, which is how they locate food sources. Not all plants produce essential oils, but those that are highly fragrant contain concentrated oils in various plant parts.

Plants with high amounts of essential oils and strong scents create an environment too intense for an ant's sensitive olfactory, causing the insect to avoid the source. Some plants also contain pyrethrins, a substance that affects the nervous systems of ants causing paralysis and other plants attract predators that feed on ants.

Here are 14 aromatic plants to grow around the foundation of your home and outbuildings to help deter ants.

Tip

You can also grow some plants in pots or harvest leaves and place them in spots inside your home, like windowsills, under sinks, and in the pantry where ants can get in and are drawn to food sources.

Mint

Of the dozens of varieties of mint, peppermint and spearmint contain high amounts of essential oil and are strongly scented. Mints are easy to grow and make a nice walkable, fragrant ground cover but they do spread rapidly. Both the odor and oil of mints are repellant to ants.

• Name: Mint (Mentha spp.)

• Hardiness Zone: 3 to 10

• Light: Part shade

• Water: 1 to 2 inches per week

• Mature Size: 1 to 2 feet tall with rapid spread

Rosemary

Rosemary is a highly versatile, aromatic herb that can be grown outdoors as a tender perennial in many growing zones and also indoors in pots. Strong evergreen scent and long needle-like leaves will cause ants to do an about-face when they encounter a rosemary plant. It also boosts the efficacy of other natural insecticides such as pyrethrins.

• Name: Rosemary (Salvia rosmarinus)

• Hardiness Zone: 5 to 9, variety dependent

• Light: Full sun

• Water: Allow soil to dry between watering

• Mature Size: up to 6 feet tall, 4 to 5 feet wide

Catnip

Catnip has been used as an insect repellent as far back as ancient Greece adversely affecting a number of nuisance pests including ants. This perennial is easy to grow, makes a potable tea, and is also known for sending your feline into a frenzy. Catnip has a heavy, musty odor with slightly hairy stems and leaves; both features that ants avoid.

• Name: Catnip (Nepeta cataria)

• Hardiness Zone: 3 to 7

• Light: Full sun

• Water: Drought-tolerant

• Mature Size: 2 to 3 feet tall and wide
  

Sage

Most people associate garden sage with the holiday turkey, but just a little bit of this potent herb goes a long way. There are a number of varieties of sage but garden sage is the most strongly scented with volatile oils. Sage leaves contain the natural chemicals thujone and camphor which are toxic to ants. This perennial also attracts snails and slugs that feed on ants.

• Name: Sage (Salvia officinalis)

• Hardiness Zone: 4 to 10

• Light: Full sun

• Water: Evenly moist

• Mature Size: 2 to 2 1/2 feet tall, 2 to 3 feet wide

Pennyroyal

Pennyroyal is another herb with use as an insect repellent that dates back centuries. The spiky blooms, along with the plant's musky, minty odor, deter ants, mosquitoes and flies. Leaves can be rubbed on pets to repel fleas but consumption of the potent essential oil is toxic to people and animals.

• Name: Pennyroyal (Mentha pulegium)

• Hardiness Zone: 6 to 9

• Light: Full to part sun

• Water: Consistently moist

• Mature Size: 6 to 12 inches tall, 3 to 6 feet wide

Citronella Grass

Citronella plant, Pelargonium citrosum, and Citronella grass, Cymbopogon nardis, are two completely different species often confused as insect repellents. The citronella plant is a type of lemon-scented geranium with a much lower level of essential oil than Citronella grass. To keep ants and other pests away from outdoor living areas, grow this perennial grass in large pots or as an annual in northern zones.

• Name: Citronella grass (Cymbopogon nardis)

• Hardiness Zone: 10 to 12

• Light: Full sun to part shade

• Water: Daily watering

• Mature Size: 6 feet tall, 4 feet wide

Eucalyptus

Eucalyptus has a high level of essential oil with a sharp, biting scent the sensitive antennae of ants cannot tolerate. This potent herb is a genus of fast-growing trees and shrubs native to tropical climates. Twigs of the rounded, fragrant leaves are available at garden and craft shops in cut form and can be used in decorative elements around the home to keep ants at bay.

• Name: Eucalyptus (Eucalyptus cineria)

• Hardiness Zone: 10 to 12

• Light: Full sun

• Water: Weekly watering, drought-tolerant

• Mature Size: 6 to 53 feet tall, 2 to 15 feet wide

Lavender

All varieties of lavender contain essential oils with a pleasant, sweet, perfume-like fragrance. Leaves, buds, and flowers of this tender perennial are all highly fragrant and too strong for almost all insects except bees. Lavender has a clumping growth habit with pink, purple, blue, and white flowers on spikes that rise above the foliage. It works well in flower beds, pots, and as a companion plant in the vegetable garden.

• Name: Lavender (Lavandula spp.)

• Hardiness Zone: 5 to 9

• Light: Full sun

• Water: Drought-tolerant

• Mature Size: 2 to 3 feet tall, 2 to feet wide

Bay Laurel

In temperate zones, Bay Laurel is usually grown as a small, potted tree overwintered indoors. Leaves emit a sharp bitter odor that repels ants and other insects. Dried, crushed leaves can be sprinkled on windowsills, countertops, and in the pantry to deter ants attracted to food sources in your kitchen.

• Name: Bay Laurel (Laurus nobilis)

• Hardiness Zone: 8 to 10

• Light: Full sun, part shade

• Water: Consistently moist

• Mature Size: 10 to 60 feet tall, 5 to 20 feet wide

Garlic

All members of the allium genus carry a strong scent and garlic, in particular, is off-putting to almost all animals and insects including ants. Bulbs, which are made up of several cloves, give off a sharp, biting scent that gets very strong when cloves are cut or removed from their paper-like coverings. Garlic is an annual, planted every year, and can be grown in pots.

• Name: Garlic (Allium sativum)

• Hardiness Zone: 4 to 9

• Light: Full sun

• Water: 1 inch per week

• Mature Size: 12 to 18 inches tall, 6 to 12 inches wide

Thyme

Thyme serves multiple purposes around the home and garden as a culinary herb, perennial flowering herb, and walkable groundcover. A number of varieties and cultivars are available including citrus-scented thymes. Thyme's flowers attract ladybugs which help control ant populations by consuming aphids.

Many types of plants attract aphids, sap-sucking insects that leave behind a sugary substance called honeydew highly attractive to ants. Controlling aphids in your garden and on houseplants eliminates a major food source for ants.

• Name: Thyme (Thymus vulgaris)

• Hardiness Zone: 5 to 9

• Light: Full sun

• Water: Bi-weekly to monthly

• Mature Size: 6 to 12 inches tall and wide

Tansy

The plant is known for its button yellow flowers and deep root system, but the leaves contain thujone repelling ants and other insects by giving off a pungent camphor-like odor. Tansy is a perennial plant considered invasive in parts of the United States and is difficult to eradicate once established.

• Name: Tansy (Tanacetum vulgare)

• Hardiness Zone: 3 to 8

• Light: Full sun

• Water: Water weekly

• Mature Size: 3 to 5 feet tall, 12 to 18 inches wide

Marigold

Marigolds deter ants in two ways. The pungent fragrance of the flowers and foliage is too intense for them, and marigolds also host a number of other insects and invertebrates that eat ants.

Marigolds are annual flowers and a favorite all-around companion plant for many gardeners. They are also grown as summer blooming, bedding plants and thrive well in pots.

• Name: Marigold (Tagetes spp.)

• Hardiness Zone: 2 to 11

• Light: Full sun

• Water: Water weekly

• Mature Size: 4 to 48 inches tall, 6 to 24 inches wide

Chrysanthemum

Chrysanthemums, both annual and hardy varieties, contain natural insect-repelling substances called pyrethrins which adversely affect the ant's nervous system causing paralysis. These are traditional autumn flowers grown both as annual and perennial holiday decorations.

• Name: Chrysanthemum (Chrysanthemum morifolium)

• Hardiness Zone: 3 to 9

• Light: Full sun

• Water: Keep soil evenly moist

• Mature Size: 2 to 3 feet tall and wide

Frequently Asked Questions

What scents do ants hate?

Most plants that emit any type of strong scent will deter ants which have very sensitive olefactory receptors in their antennae. Scents most offensive are sharp, pungent odors like pine and camphor and musty scents like sage and catnip.

What plants attract ants?

Peonies emit a nectar especially attractive to ants. Other flowers that draw ants include roses, clematis and penstamon.

What plant repel ants and spiders away?

Many of the same plants that repel ants also repel spiders which avoid strongly scented plants. Mint is especially effective for repelling both.

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