The Deschutes Land Trust is so appreciative of the support our community has offered to increase habitat for monarch butterflies and other pollinators! Thank you! As we continue to work together to increase monarch habitat in Central Oregon, we are asked lots of questions about monarchs, milkweed plants, and seed starting. We hope this handy guide will help you as you continue to add habitat to your gardens, backyards, and balconies!
Monarch Butterfly Questions
What kind of monarch butterflies do we have here?
The butterflies in our region are Western monarch butterflies. Their range is generally considered west of the Rockies with overwintering sites along the California coast and breeding throughout the west from Arizona to Idaho.
- Eastern monarch butterflies overwinter in Mexico and breed in the Midwest.
- Both are genetically similar, but are considered sub-populations.
- Dig deeper: Some portion of Western monarchs travel to Mexico for the winter, and some portion of Eastern monarchs travel to the western United States after overwintering in central Mexico, and/or there is interbreeding of Eastern and Western monarchs during the breeding season. The relative rate of exchange between the Eastern and Western populations is currently unknown.
Why don’t I see monarch butterflies everywhere?
Because of habitat loss and decline in overall populations. That is why we are planting more milkweed!
Are you sure Central Oregon is part of their range? I don’t see them here.
Yes! Because of habitat loss and population decline they are less abundant than they would have historically been.
Can I raise monarch butterflies?
The very best thing we can do to help support monarchs is to plant pesticide-free native milkweed and other native pollinator plants that collectively provide blooms spring through fall.
I saw an orange butterfly! Was it a monarch?
Due to habitat loss and decline in overall monarch butterfly populations, monarch sightings in Central Oregon are relatively rare. Since monarchs are poisonous to birds, there are many other butterflies that imitate the monarch’s orange and black patterning, to make birds think they are also poisonous to eat. You can see some common butterflies that are mistaken for monarchs on our blog: Five Butterflies That are Not Monarchs.
Milkweed Plant + Planting Questions
How much sun do my showy milkweed plants need?
Your milkweed will be happiest in a sunny area in your garden. It doesn’t have to be full sun, but your plant will be happiest if it has a decent amount of sun (4-8 hours every day, depending on strength of the sun).
How closely together should I plant my milkweed plants?
It’s best to plant your milkweed seedlings in clusters, with ~8” between plants. Milkweed takes years to mature and spread/fill in, so if you’re lucky enough to have a monarch stop by and lay eggs in the early years, the emerging caterpillars won’t have to travel as far to find additional food. And you can always thin out your patch of milkweed 5-6 years down the road if it seems to be getting overcrowded.
Plan for rhizomes. Once your milkweed becomes established, it will begin spreading underground via its rhizomes. If you’d like to control spread, consider planting in a raised bed, or better yet give it the space to spread and grow.
Rhizomes, what are rhizomes?
Rhizomes are underground plant stems that allow a plant to spread and send up new shoots. Milkweed is VERY good at spreading via its rhizomes. It can take over and out compete other plants, so plan for it, instead of fighting it.
How much water does my showy milkweed need?
Your milkweed will continue to need regular watering in order to establish their roots. You’ll need to be patient, as native plants can take 2-3 years to get established or to even bloom!
How can I reduce transplant shock?
Wait until the threat of frost has passed and then set the seedlings (in their growing containers) outside for several days before transplanting. You can also cut the milkweed seedling back to just below the first leaf before planting, which helps with the adaptation to the new outdoor conditions.
You can also plant your milkweed seeds in newspaper pots or peat pots and plant the pots themselves directly in the ground. If you are using peat pots, cut the bottom of the peat pot out right before planting to help the roots grow.
Will milkweed harm horses/livestock/pets?
Milkweed contains toxins that can be harmful to pets, livestock, and people if ingested.
How can you keep deer from eating milkweed? And will monarchs be able to access milkweed in a greenhouse or hoop house under fencing?
When milkweed is young and first getting established, the deer will munch on it. So protecting it at that stage can be helpful. In order to provide access for monarchs while blocking deer, tall fencing is best. You can also use mesh wire caging with large enough openings for monarchs to fly through. Once it matures, the deer tend to leave milkweed alone to avoid its bitter taste.
Timing may help a little too. Monarchs don't really arrive here in Central Oregon until late June or even later so that is when you would want your milkweed "open for business" so to speak!
I’m not sure if my milkweed survived the winter since they died back. Is there a way to identify if they will re-emerge?
Showy and narrowleaf milkweed naturally die back in the late fall, then send up fresh shoots in the spring. Please leave the dead stalks as nesting cavities for bees and other critters. In the spring, be patient, as milkweed often takes its time to re-emerge.
Can I cut back my milkweed in the fall? When should I do it?
Milkweed naturally dies back in the fall. It's best to wait to cut last year's milkweed stalks in the spring, after fresh growth begins. That way solitary bees and other insects can use the old hollow stems for nesting or overwintering protection.
Where can I get narrowleaf milkweed?
Narrowleaf milkweed is a milkweed native to Central Oregon. Experts suggest planting both species of milkweed increases monarch habitat resilience to climate changes and some studies have even shown that when multiple species are present, monarch butterflies will lay more eggs. The Land Trust does not currently have a supply of narrowleaf seeds for distribution, but starter plants can often be found at local native plant nurseries or at Land Trust plant giveaways. Native plant nurseries to try include Clearwater Native Plants in Redmond, Great Basin Nursery in Bend, WinterCreek Native Plant Nursery in Bend, or Madras Garden Depot.
When purchasing your plants, be sure they are neonicotinoid free. This nasty pesticide is not only incredibly harmful for monarchs and other butterflies, but also bees and beneficial insects/pollinators. In addition, neonicotinoids get into a plant’s cells, which means when they re-emerge each spring, the pesticide is still part of the plant (not only in the nectar of the blooms, but also in the leaves, which monarch caterpillars eat).
How long before my milkweed is big/mature enough for monarchs?
Female monarchs will lay eggs on tiny milkweed seedlings as well as mature milkweed leaves and blooms. So no milkweed is too young for eggs/caterpillars!
Showy milkweed doesn’t typically yield blooms until year 3-4, so that’s when it becomes an important nectar resource for adult monarchs and other insects.
Narrowleaf milkweed tends to produce blooms much sooner, often within the first year.
When will my milkweed bloom?
Showy milkweed is slow to mature. Its impressive pink blossoms often don’t appear on plants for 3-4 years.
When will I start seeing monarch butterflies on my milkweed?
The monarch population has dropped precipitously in recent years—primarily due to habitat loss, pesticides, and climate change. The dwindling population has reduced the number of monarch butterflies we see today. With the restoration work happening at Land Trust Preserves and beyond (thousands of plants have been planted at Land Trust Preserves and throughout Central Oregon with a variety of partners) and with neighbors like you planting milkweed, we are hopeful we will spot more monarchs in the future. In the meantime, know that your milkweed is providing important nectar and pollen to other insects.
You can keep track of sightings in this Milkweed Mapper to log milkweed you've planted and seen growing in Central Oregon for kicks!
What about growing non-native milkweed in Central Oregon?
It’s best to grow milkweed that is native to Central Oregon. Different species of milkweed have different levels of cardenolides (the substance in milkweed that helps make the caterpillars and adult monarchs unpalatable and poisonous to predators) and different growth habits (bloom time/duration, senescing patterns, water needs, shade tolerance, etc). The monarchs that migrate through our area have evolved with our local, native milkweed. Planting other species of milkweed does not help the monarchs as much as native milkweed and can even be harmful.
Seed Starting Questions
What are the specific growing dates for starting milkweed seeds?
In general, we’d recommend starting your milkweed seeds in mid-April if you have a good, sunny window indoors to place your milkweed pots. If you have a window with less sun or tend to be lax with watering requirements, we'd recommend starting your seeds in mid-March. We suggest planting your milkweed plants outdoors after the last frost date. The general last frost date in Central Oregon is May 25 (Memorial Day weekend).
What’s the depth and spacing for milkweed seeds?
Sow milkweed seeds by scattering them on the soil surface 1/4-1/2 inch apart, and then cover them with about 1/4 inch of additional soil.
What do I do after I plant my seeds?
Continue to water (don’t drench!) and sun your seedlings (on a sunny windowsill) until they’ve sprouted and are several inches high. Then transplant them into your planting location. See above for spacing and other requirements.
Milkweed likes warmth! Seed warming mats or warm weather are super helpful for starting your seeds. You can even start them in the summer and plant them outside in the fall.
How do you cold stratify milkweed seeds?
Here is how to get started on cold stratification:
- Clean the seeds and soak in tepid water. Once the seeds have plumped up a bit, transfer them to a damp, unbleached paper towel or coffee filter.
- Spread the seeds out, making sure there's a little space around each seed. Cover with another damp paper towel to keep moist on top and bottom. Seal in a ziploc bag and place in your refrigerator for 6-8 weeks.
- Check the seeds once a week to make sure they're moist, but not moldy. If they are moldy, rinse them off, spread them out on two new damp paper towels, seal them back into the ziploc, and put back in the refrigerator.
- Once the seeds start to germinate (you’ll see a little stem emerge from the seed), you can remove them from the refrigerator. Plant as above.
Do I have to cold stratify milkweed seeds?
Many growers and groups recommend cold stratification (subjecting seeds to cold and moisture for a time) to ensure that seeds germinate. However, the Land Trust has had success skipping this step and just starting seeds without stratification. It’s recommended, but not required.
Can I harvest seeds from my mature milkweed?
Yes, if they are free of pesticides.
Can I harvest milkweed seeds from any milkweed?
Unfortunately, pesticides like neonicotinoids are systemic and persist in plants. This means we have to be careful to grow from untreated milkweed seeds. Only harvest seeds if you know the plant has not been treated with pesticides.
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