If you want monarch butterflies to visit your garden this fall and spring, planting milkweed in your landscape is a must! Not only is milkweed a great nectar source for thirsty pollinators, it is also THE ONLY host plant that monarch butterflies lay their eggs upon. Milkweed is also a great nectar source for monarchs and many other pollinators; fortunately for us, it comes in many varieties to choose from.
Along with providing a host and nectar source for monarch butterflies, milkweed also provides aesthetic beauty in your landscape with its unique blooms. It is, however, picky about how it is transplanted and cared for. Today I’m going to give you some easy steps and tricks of the trade for successfully planting your milkweed. Fall is the best time to plant for our native pollinators and they are headed here soon. Time to get busy! (Featured image: Lisa Mulroy. Monarch butterfly fresh from chrysalis.)
6 Steps for Successfully Planting Milkweed
Here are our recommended steps for planting milkweed. More info for each step can be found following the list.
- Choose a mostly sunny location that drains well.
- Dig only as deep as the rootball and no more than about double the width.
- Fill hole with water and let drain completely before planting.
- Cut the pot off of your milkweed transplant rather than pull it off so you don’t disturb roots.
- Set the milkweed level, or slightly higher, than ground level then backfill with soil.
- Water to get established, then set irrigation timer.
More About Butterfly Milkweed Planting Tips
1. Sun and Drainage: Most milkweed does best and offers better blooms when planted in an area that receives full sun to light shade. In San Antonio, most milkweeds do great when they receive full sun for most of the day, but a little shade in the hottest of the afternoons can be refreshing and offer them a break when we have some real scorchers.
Well-draining soil is imperative for the success of milkweed. This is super important! Soil that stays wet for too long will result in root rot and eventually death to your milkweed plant. If you are unsure if your soil drains well where you are wanting to plant, dig a 12″ x 12″ hole, fill it with water and let it drain. The water should completely and quickly drain from the hole, like in 15-20 minutes. If it doesn’t, that’s not the spot for planting milkweed.
*Note on soil: We have a huge variety of soils in Texas. Clay soil does not drain super fast and will need to be amended with a lot of perlite and peat to get the water moving through it. Rocky, limestone soils like in the Hill Country usually drain pretty well. If you are in doubt, plant your milkweed in containers with a quality potting soil like FoxFarm Happy Frog mixed with a lot of perlite (kind of like a succulent potting soil). It may just be easier than all the inground soil amending you may have to do.
2. Dig Your Hole: Planting milkweed too deep is a common mistake for novice butterfly gardeners. Milkweed should be set no deeper than the rootball. In other words, the top of the rootball soil that is in the nursery container should be set level to the top of the ground (or just slightly higher). Basically, if you dig a hole and set your milkweed plant in it, you should be able to lay a ruler across the hole and plant and it should be level or a little higher in the center. Got it?
3. Water Before Planting. You should always water both your nursery plant in its container, and the hole you are going to plant in before setting your milkweed in the ground. Fill up the hole with water and allow it to completely drain before moving on to planting. (Do the test in step 2 if you are unsure you have good drainage).
4. Cut Your Pot: Milkweed plants have long taproots that do not like to be disturbed when being planted. Do NOT use the common method of flipping your pot over and squeezing the sides and roughing up the roots like we commonly do with other plants. Milkweed is extremely sensitive about having their roots messed with. Take time and be careful, using the method in the paragraph below to get your milkweed safely out of the pot. (Once you have milkweed and it produces seed, try direct seeding in our warmer months. Milkweed grows easily from seed and you don’t have to worry about transplant shock and damage to any taproots!)
Use a utility knife and carefully cut around the edge of the bottom of your pot of milkweed from the nursery. Set the pot into the bottom of the hole you dug to check for correct hole depth (see tip 3). Use the utility knife to make a couple of vertical cuts down the sides of the pot so you can basically “peel” the pot away from your milkweed, leaving all its roots intactand as undisturbed as possible.
5. Level Milkweed and Backfill Hole: This is the time to make sure your milkweed is standing tall and straight, not leaning to the side. You can also check the level that you are planting it again since the watering may have created a deeper depression. Only if needed, add a bit of soil to bottom of hole to raise the rootball slightly higher than the existing soil grade. Planting on a berm where the rootball is slightly higher than ground level greatly reduces your risk of root rot.
Backfill hole with native soil, gently patting and firming soil around rootball, filling the rest of the hole. Tamping the soil slightly helps eliminate air pockets in the soil. Air pockets can prevent the natural flow of water to roots and roots don’t even grow in air pockets, so you don’t want them. A gentle touch is best, we’re not trying to compact the soil either.
6. Water In and Maintain: Water immediately after planting, focusing on the soil. No hard blast of water is needed, a nice slow stream is better. Water as needed after planting your milkweed to help get roots established. You may have to water more or less depending on soil type and milkweed variety. Please see more info in the first bullet point below. Your finger is the best moisture meter out there, and it’s free! Stick it into the soil and feel for moisture. If moist, don’t water, if very dry, water.
Butterfly caterpillars on Common Milkweed.
Photo credit Laura Jarvis: The Butterfly Landing
7 More Facts About Milkweed
- Milkweed can be very finicky about water. Too much can be a death sentence to most milkweeds, however, some can tolerate more water than others. It is good to research the milkweed you wish to purchase to know the difference. For refererence: Zizotes, Antelope Horns, Pineneedle, Texana, Common, Showy and Tuberosa or Butterfly Weed milkweeds really cannot tolerate wet soils at all. Soil should bascially be amlmost completely dry before watering again. Tropical, Swamp, Balloon Plant, and Giant Milkweed Tree are more tolerant of water.
- Don’t use ANY pesticides on milkweed (even organic or “safe soaps”). You will kill off all the butterfly caterpillars that feed on it and harm the butterflies drinking from it along with any other beneficial insects that visit it.
- Milkweed will most likely get aphids. So what! Ladybugs or Green Lacewings will find them and eat them, or you can blast them off with a spray from the hose (but alsways check for eggs on milkweed first). Let nature do the dirty work for you.
- The milky, sticky sap on milkweed can be irritating to skin. Wear gloves.
- I think native milkweeds are BEST, but I also don’t think tropical milkweed is “bad”, and I do use it in my garden. Just be responsible and follow these necessary precautions: Tropical milkweed MUST be cut all the way back after the fall butterfly migration to deter disruption to the natural migratory pattern of monarchs and to help eliminate the spread of OE spores (a debilitating infection that adult monarchs can contract. Educate yourself on this a little more here.) We actually advise to cut your tropical milkweed back at least 2 times a year (June and November). After cutting back your tropical milkweed, let the wounds heal closed (a couple of days, and then you can spray it with a 50/50 mixture of water and isopropyl alcohol (91% strength) to further sterilize the plant. Don’t spray during the heat of the day. To use or not use tropical milkweed is a hot topic in the gardening community. We encourage all of you to do due diligence and research and decide for yourself.
- Milkweeds may go dormant at times and lose all their foliage, so it is important to mark where you have planted them so as not to disturb the roots for future growth.
- Milkweed can be hard to find at garden centers. When you come across it, buy it. Collect seeds and grow your own.
As I wrote this blog, I had four monarch chrysalises eclose. The beauty and awe of watching these magnificent creatures evolve is why I plant milkweed in my landscape. To give myself this gift of witnessing a truly miraculous event, over and over is my why!
Stay tuned for more blogs on specific milkweeds and other amazing pollinator plants that you should try in fall!
~The Happy Gardener, Lisa Mulroy