When you think about creating an oasis in your garden for butterflies, you probably don’t think about herbs. But you should! Herbs provide a valuable food source for butterfly larvae and nectar for adult insects. Besides encouraging butterflies to swoop in for a visit, herbs look and smell great as they grow. And there’s one more benefit to planting herbs: they’ll liven up your meals.
But before running out to the nearest garden centre, do a little research. First, check which butterflies inhabit your region. Then, find out which herbs those butterflies prefer. Finally, choose plants that are well suited to the growing conditions in your garden.
Determining Which Butterflies Will Visit
Before you start choosing plants, figure out which butterfly species inhabit your area. Different species prefer different food sources. Once you know which species live in your region, you can research which plants they prefer as larval food sources and for nectar. The Butterflies of Ontario website and the Canadian Biodiversity Information Facility website are both terrific resources for this purpose.
Growing Conditions and Hardiness Zone
Plant growth is affected by light, water, nutrition, soil conditions, and temperature. It would be a waste of money to purchase seeds or seedlings that won’t grow in your garden. Take a good look at your garden patch. Buy plants that are suited to your growing conditions or figure out how those conditions can be mitigated.
For instance, sunshine and warmth are particularly important in butterfly gardens. Most flowering plants–including herbs–require full sun to flourish. Additionally, butterflies (which are ectotherms) need sunshine to keep their muscles warm so that they can fly. If your garden patch isn’t currently in full sun, can it be moved? Could a small secondary patch be established in the sun? Could pots and planters be used and moved into a sunny spot?
Also, find out your hardiness zone if you don’t already know it. Many herbs are perennials and will return the next spring as long as they’ve survived the winter. If you need help figuring out your zone, check the hardiness maps available on the Canadian and American government websites.
Herbs as Larval Food Sources
According to the Canadian Biodiversity Information Facility website, the Apiaceae family of vegetables and herbs is attractive to swallowtails. In particular, black swallowtails (in eastern Canada) and anise swallowtails (in western Canada) will choose herbs within this family as a food source for their larvae.
Anise is hardy perennial in Zones 4-9. It doesn’t transplant well and is best sown in large containers or direct in the soil. Anise prefers full sun and well-drained soil.
Caraway is hardy perennial in Zones 4-10. It will grow in full sun to part shade. It’s best sown directly in the soil in autumn or very early in spring.
Dill is an annual that performs best in cooler temperatures. In Zone 9 and above, it will have a limited growing season. Dill prefers full sun.
Fennel is a tender perennial in Zones 6-10 but is most commonly grown as an annual. Fennel grows best in full sun and moist soil. Fennel is classified as an invasive species in California and should not be grown there. It’s best to check with your municipality before planting fennel, to determine its status in your region.
Lovage is hardy to Zone 4 and will take three years to fully mature. It grows best in full sun but will tolerate partial shade. The plants are tall and may take over a small herb garden as they spread.
Parsley is hardy in Zones 4 through 9. It is technically a biennial but is most commonly grown as an annual, particularly in cooler zones. It requires full sun.
There are a few herbs outside of the Apiaceae family that butterflies also seek out for their larvae. These include borage, mint, sage, and tansy, among others. For a comprehensive list of these herbs, and the butterfly species that seek them out, check The Butterfly Website.
Herbs as Nectar Sources
Butterflies will help themselves to the nectar produced by most flowering herbs. In addition to those listed as larval food sources above, the following common herbs will attract butterflies to your garden with their nectar:
Chives/Garlic chives are hardy in Zones 3 through 10. In colder zones, they can be grown in pots and overwintered indoors. Chives are vigorous when planted in full sun and fertile, well-drained soil. In poorer conditions, they’ll still grow but they won’t thrive.
Lemon balm is hardy in Zone 5 and above. It prefers cooler conditions and shade, though it will grow in the sun. If planting for butterflies, try to position lemon balm so that it gets morning sun but is protected from the hot midday sun.
Rosemary is hardy in Zones 7-10. In colder climates, it can be potted and overwintered indoors. Rosemary grows best in full sun and well-drained soil.
Thyme is hardy to Zone 4. It grows very slowly and likely will not have stems available for harvest during the first two years. It grows best in full sun.
Lavender is hardy in Zones 5-8. Like chives and rosemary, it can be grown in pots in colder climates and overwintered indoors. During the growing season, it prefers full sun.
Invasive Herbs
As noted above, some herbs can be invasive or aggressive in the right growing conditions. While it’s nice to watch your garden fill in with very little cost or effort on your part, invasive herbs can choke out other plants and take over your garden.
All mints, pennyroyal, comfrey, bee balm, and lemon balm are considered highly invasive. However, it’s not difficult to discourage spreading. Invasive herbs can be planted in pots, which can then be sunk in soil (to keep their roots contained) or left above ground.
If you need to overwinter a potted herb, it’s best brought into a protected but cool building, like an unheated shed or garage. The plant will still need sunlight and good air circulation. It will also need to be watered on occasion. In the spring, make sure all risk of frost has passed before moving your potted herbs back outside!
Herbs are a delightful addition to any garden. Whether you’ve planted herbs specifically to attract butterflies, or butterflies end up being serendipitous visitors, you also get to enjoy the colour and scent of the herbs–as well as their culinary perks.
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