Although horticulturalists don’t categorize ants as a garden pest, most people consider the ant an unwelcome tenant in the flower garden. Ants are aggressive, especially the notorious fire ant of the South, which seems to expand its territory northward year by year. Some ants maintain a mutually beneficial relationship with aphids. Ants can also ruin an otherwise perfect spring bouquet of peonies. It’s unreasonable to try to exterminate ants completely in a flower garden, but you can control them without resorting to harmful chemicals.
Sometimes the very things we use to care for our gardens have the unfortunate side effect of drawing ants. The compost pile you nourish attracts ants when it sends the sweet aroma of rotting cantaloupe rinds and banana peels into the air. To discourage ants, maintain a hot compost pile, using the proper ratio of green and brown ingredients. An elevated compost tumbler can also prevent ant infestations.
A thick layer of wood chip mulch is important for weed suppression and moisture retention in the garden but also creates a cozy habitat for many ant species. If this makes you dread digging in the soil for fear of unearthing a swarm of angry ants, try an inorganic mulch like crushed rocks, ground-up tires, or synthetic landscape fabric. These materials won't enrich the soil, so you may still want to add compost or manure at planting time.
Create Homemade Ant Repellent
Ants are very sensitive to odors, as any picnicker can tell you. Just as they are attracted to sweets, certain smells repel them. Experiment with cotton balls soaked in ant-repelling essential oils. Ants detest mint, camphor, tansy, and clove oil. You can also grow your own ant repellent in the vegetable garden. Place hot peppers in a blender with a bit of water to create a dense mash, which you can spread in problem areas.
An Easy Way to Kill Ant Colonies
Baits laden with insecticide are more likely to target just the ants. You can mix a cup of borax with a cup of honey or jelly and place it near an area of ant activity. Ants will feed and carry this toxic mixture back to their queen, which will result in the death of the colony. You must be patient to see the results of this method, for the borax is a slow-acting poison, which gives the ants time to distribute the toxin to others. If this homemade solution is too messy, you can purchase ready-made boric acid ant bait.
The same pesticides that kill ants are also toxic to many insects that gardeners want around the flowerbed, like Monarch butterfly caterpillars and ladybugs.
Keep Ants off Flowers
Ants are attracted to sweet foods, and this includes many fruits and some nectar-rich flowers. Peonies, in particular, seem to attract ants just as buds turn to blossoms. Although ants rarely inflict damage to flowers or fruits, no gardener wants to mar the joy of harvest with a handful of swarming ants. You can use sticky traps to prevent ants from ascending the plant of concern. Buy a commercial sticky product, such as Tanglefoot, or make your own sticky traps from adhesive paper strips wrapped around the base of the plants.
There are two ways to deal with ants on peonies. Cut the flowers when they have fully opened, as ants are attracted to the sucrose that collects on buds. If you cut the flowers in bud, refrigerate them immediately. Within 24 hours, the ants will become very sluggish, making it easy to wipe them off the buds.
If you notice a congregation of ants gathering on one of your garden specimens, be suspicious. Ants are purposeful creatures, not given to leisurely gatherings. Look closely, and use a magnifying glass if necessary: you will probably discover an infestation of aphids. The ants are enjoying the sweet honeydew excreted by the aphids. In exchange for this nourishment, the ants protect the aphids from their enemies, attacking such beneficial insects as ladybugs. You must treat the plant-damaging aphids first; the ants will seek food elsewhere.
Control Fire Ants
Fire ants deserve less of the flower gardener’s tolerance and sympathy. These aggressive invaders can crawl quickly up the gardener’s arm or leg, delivering dozens of painful bites before the victim detects them. They also prey on wildlife like lizards, frogs, spiders, and even birds in the garden. If you have any fire ant mounds on your property, you must destroy them. Cover the mound with a container, and pour boiling water around the container. Wait one minute, then turn over the container with a stick and pour an additional gallon of boiling water into the ants seeking refuge in the container. Repeat as necessary.
The Benefits of Ants
Don’t despair if you have more ants in your garden than you’d like. Ants aerate the soil, function as pollinators, and eat the eggs and larvae of fleas and other pests. Consider purchasing an ant farm to amuse the children, and learn more about the ways of this social insect.
Getting Rids of Ants in Your Vegetable Garden. UC Master Garden Website