Which Milkweed Species Grow Well in Containers?
Container gardening ideas for your monarch butterfly garden consist of both nectar flowers and milkweed plants. Even better, are the butterfly plants that serve both purposes.
But why would you want to grow milkweed in a container?
Put pots on raised beds, move them around in the garden, or bring containers to a patio for easier viewing of butterflies and caterpillars.
2. Raising Monarchs
When you raise monarchs on a potted plant, you don’t have to constantly switch out their milkweed supply. However, make sure if a pot has been sitting outside that you thoroughly check the leaves and container for hungry predators!
Alternative ideas for sterilizing plants would be spraying down stems with a 10-20% bleach solution or using a hydrogen peroxide mix for sick and fungusy plants
3. Grow Above your Hardiness Zone
If you grow non-native milkweed varieties, you can buy new seeds/plants annually or you can overwinter in containers. This gives you larger plants to start the season and also saves time and money getting new plants started.
4. Create New Plants with Stem Cuttings from your Container Plants
Here are SEVEN milkweed container gardening ideas for your butterfly garden:
Asclepias Incarnata (Swamp Milkweed)
This is probably the best option if you want to stick with natives varieties. Each fall, leave a couple inconveniently-seeded first year swamp plants in your garden and mark them.
Incarnata doesn’t have tap roots, so it’s easy to dig up and replant. It’s also a favorite host plant and nectar flower for monarchs.
The advantage to using second year plants? Several stalks will emerge and your container will have a long bloom period in summer.
Asclepias Curassavica (Tropical Milkweed)
Asclepias curassavica blooms all season long so it works great in containers. It also grows shorter than swamp milkweed so a potted plant will fit better in a large caterpillar cage, should you decide to raise monarchs.
In our northern garden, we typically use potted tropical milkweed once to raise monarchs to release for the fall migration. Make sure to take the disinfecting precautions listed above if you reuse potted plants in the same season…this goes for any milkweed variety you are reusing.
Asclepias Perennis (Aquatic Milkweed)
This is an exciting native option for containers because it blooms repeatedly with pretty white flowers similar to swamp milkweed. Perennis leaves also stays viable for monarch caterpillars throughout the season. Suggested for USDA hardiness zones 6-9. Grow Annually or overwinter in cooler regions
Asclepias Tuberosa (Butterfly Weed)
This widely used native milkweed has more compact growth, although it does have underground rhizomes, so I would suggest using a 10″ pot or larger, depending on the size of your plant.
Oxypetalum Caeruleum (Tweedia Milkweed)
This is the only milkweed with true blue flowers and a beautiful container option. It’s a climbing vine, and I’ll be sure to report our experience growing it in year 2. I would not recommend depending on this variety as a host plant, although it is a viable milkweed option for monarch caterpillars.
Cynanchum Laeve (Honeyvine Milkweed)
This native climbing butterfly plant can be an aggressive spreader, so why not try it in a container so you can reap all of the milky benefits without the hassle of runaway rhizomes?
Gomphocarpus Physocarpus (Balloon Plant)
This does not spread aggressively in my northern growing experience. We are currently growing its closest milkweed relative, Gomphocarpus fruticosus (swan milkweed), and that variety does seem to have more aggressive tap roots…go figure!
Best Soil for Milkweed Containers?
Keep in mind there are over 25 varieties of milkweed you could plant, so research to see if a particular milkweed variety has special soil requirements.
For the most part, using an all purpose soil mix works well for most milkweed species. I use a slow release fertilizer to give the plants extra nutrients. This does not hurt the munching monarch caterpillars.
Best Containers for Milkweed?
You can try growing any milkweed variety in pots as long as the container is large enough to accommodate the rhizomes/ tap root. Think about how long you will be growing milkweed in a particular container…will it be for just one season, or the next several?
For our annual milkweed containers, we use 10 or 12 inch pots. Consider a 14″ container for perennial containers…replant in a larger pot when the need arises.
Milkweed Container Tip- Select milkweed species that are hardy to at least one USDA hardiness zone below yours. Fence and mulch to keep plant roots from freezing, or move them to a protected area like a garage.
Use large stones at the bottom of your containers to keep them from blowing over and to give your milkweed pots good drainage.
Consider placing pots in a protected area where they won’t be subjected to winter weather extremes. For more info on protecting potted plants over winter check out this article
Keep in mind this is not an exhaustive list of milkweed container gardening ideas, but these are some of the options gardeners have reported the most success with…happy gardening!