I am located in southern Ontario zone 6a (or 6b not sure) and I am planting a cottage/pollinator garden. Last year I planted two different varieties of milk weed, an orange variety and a white blossomed one. My question is, would it be safe to plant common milk weed? I know it has a reputation for spreading but is it safe to plant in a mixed bed? I’ll be planting tulips, cone flowers, hostas, and I have the tall growing sedum as well as cardinal flower, Japanese anemone and lots of columbine which have naturalized this year. I have also tried planting Allium but they have not bloomed yet since they are under a layer of snow. Can the common milk weed also be used as a cut flower? My garden is suppose to have a double purpose, pollinator friendly as well as cut flower friendly? Thanks again!!
Thank you for contacting the Toronto Master Gardeners with your inquiry.
We applaud you for planning to plant milkweed with the Monarch Butterfly in mind. Milkweeds are well known for their role in the life cycle of butterflies, particularly Monarchs as they act as larval host plants. Adult monarchs will drink the nectar of many flowers in addition to milkweed; in fact they need sources of nectar to nourish them throughout the entire growing season. Including a variety of flowering species with different bloom times in your cottage garden will not only provide monarchs with the food they need to reproduce in the spring and summer and to migrate in the fall but planting milkweed is a great way to help other pollinators too, as they provide valuable nectar resources to a diverse variety of bees and butterflies.
There are many varieties of milkweed. There are some which thrive in full sun, in humid conditions and even in very dry conditions. The swamp Milkweed Asclepias incarnata is the plant that most people associate with the word “milkweed”. Asclepias incarnate is not as aggressive a spreader as the common milkweed Asclepias syriaca. It has a longer bloom time and as an added bonus the large deep pink umbels have an attractive odour. Asclepias incarnata grows well in full sun to part shade areas in moist well drained soil.
An earlier post titled Controlling Common Milkweed lists strategies on how to keep the more aggressive milkweed under control which you could adopt if you find your patch of swamp milkweed getting too large.
The stems and leaves of Asclepias incarnata exude a white milky sap if cut or broken, which is a common characteristic of species in the Milkweed Family, this sap can be very irritating to the skin. Also, you must remember that the more flowering stalks left on the plant the more Monarchs, bees and pollinators will be attracted to your garden.
I hope you have the pleasure of seeing many monarchs and pollinators vising your garden.