Wednesday, October 26, 2011

Monarch Butterflies in the Phoenix Area

Laura's monarch 10-25-11
Laura called me yesterday excited to see a female monarch butterfly laying eggs in her yard in Scottsdale. She was sitting on the ground looking at her milkweed searching for caterpillars, when a female appeared and eagerly looked for the perfect spot to lay her eggs. Monarch butterflies usually lay their eggs on the under side of a milkweed leaf, often on the newest and freshest growth. Funny thing, I was watching the same thing in my yard.
On Sunday morning this ragged-winged lady visited my yard laying eggs on every available milkweed. It seems like the same monarch was laying more eggs yesterday on Arizona Milkweed, Asclepias angustifolia, near my house. She flew in early and nectared on lantana and zinnias, then began choosing her milkweeds for a  future generation. The only problem is this is really late in the season for this kind of behavior. The usual life cycle of egg-larva-pupa-adult is about 30 days and it is all temperature controlled. With our cooler weather finally arriving today it can take longer. By now most monarchs are arriving or near their overwintering homes near Mexico City or the coast of California.

Reports of monarchs in the Phoenix area are the highest we have heard in recent years. But they are later than usual. Everyone seems to have hungry monarch caterpillars in their yards. If you have milkweed, check your plants for small areas of skeletonizing on your leaves or small holes - often there is a tiny caterpillar chewing there.

Laura's third instar monarch caterpillar
 Earlier in the day Laura found this third instar monarch larva in her yard. By the different sizes we know more than one female likely visited her yard. I know I have seen at least six female monarchs laying eggs in my yard since the beginning of September. While usually I have around 20 monarch caterpillars in a good year, this year I am now over 125 caterpillars! Just amazing. And Tatsuyo on South Mountain is over 100 already. These numbers are extraordinary in the Sonoran Desert.

Asclepias angustifolia
Monarch larvae are vulnerable to many predators. While a female monarch may lay up to 400 eggs in her lifetime, only about 10% will complete the full life-cycle to an adult butterfly. Ants can eat eggs, parasitic wasps can lay their eggs in the caterpillar itself, wasps can harvest the larvae to feed their young. I always try to protect a few caterpillars on one-gallon potted plants in a simple mesh laundry basket on my back patio to increase their chances of survival.

To transfer tiny caterpillars easily, either cut the leaf and move it to the new plant or use a soft, firm brush to easily move them.

Keep your eyes out for monarch pupa in odd places around the yard. Sometimes you can find them where you least expect them. Often caterpillars will wander up to 30 feet away to pupate.

Monarch sightings are higher than usual in Scottsdale, along the Salt River channel, and South Mountain. Monarchs are already reported in Yuma and Tucson, too. Of course you can also see monarch butterflies at the exhibit at the Desert Botanical Garden until mid-November.
Keep your eyes open for blue-tagged monarchs. Many have been tagged by the Southwest Monarch Study around town to monitor their migration movements throughout the state.  We are all citizen-scientists and by our keen eyes we can help better understand the monarch migration through Arizona.

Thursday, October 13, 2011

Milkweed Fall Plant Sale Check List

Fall in the Sonoran Desert is like Spring in the rest of the country - the perfect time to run to the nearest plant nursery and help your garden shine. Our soil is still warm, encouraging rapid root growth. It's a great time to create a wonderful wildlife refuge in your yard, no matter the size. Over the past few weeks at workshops around the state everyone has been asking where to find milkweed to help the monarch butterfly migration. Here is a list of plant sales and anticipated milkweed availability.

Desert Milkweed, Asclepias subulata
Best for the lower deserts including the greater Phoenix area, Yuma and Tucson. Thrives in full sun. Water twice weekly the first two years, then weekly deeply. Native plant, evergreen.
Desert Botanical Plant Sale (10/15 & 16)
Boyce Thompson Arboretum (Now through 10/23)
Baker's Nursery, Phoenix
Shady Way Nursery, Apache Junction
Master Gardener Plant Sale - Extension Office, Phoenix. 10/22

Arizona or Narrowleaf Milkweed, Asclepias angustifolia
In the Phoenix area grows best in the shade or with morning sun only. Native plant, evergreen. Water twice a week the first year, then weekly deeply.

In previous years this monarch favorite was offered at the Desert Botanical Garden plant sale (10/15 & 16). However my request for information regarding availability is unanswered as of this time. It's worth a trip to see if it is, though. The only other plant nursery that I know of that carries this shade blooming plant is Desert Survivors in Tucson (right off of  I-10 Exit 259 in Tucson.)

 Tropical Milkweed, Asclepias curassavica
In the Phoenix area grows best with morning sun, afternoon shade. A non-native (native to Mexico) but a monarch magnet.  Available in orange and yellow flowers and also an all yellow cultivar that is hardy in colder temperatures. Frost tender but often will regrow from roots.
Desert Botanical Plant Sale (10/15 & 16)
Boyce Thompson Arboretum (Now through 10/23)
Easily grown from seed. (Butterfly Encounters)

 Pine-leaf Needle Milkweed, Asclepias linaria
This milkweed does best with some afternoon shade in the warmest parts of the desert. In Southeast Arizona monarchs use this milkweed extensively as a host plant. In the Phoenix area we do not see as much larval activity, but it is a strong monarch nectar plant. We need more data on this milkweed. Let us know if you see monarch activity on this native milkweed.
Usually found at the Desert Botanical Garden (10/15 & 16), Shady Way Nursery in Apache Junction, Boyce Thompson Arboretum (Now through 10/23).

Giant Milkweed or Sodom Apple, Calotropis procera
A non-native milkweed originating in Africa and found in Mexico. One of the few milkweeds that will die back in winter then vigorously regrow in Spring. This milkweed has spectacular fragrant flowers that bloom all summer and seed pods the size of grapefruits. Takes full sun well with deep watering.

Available only at Baker Plant Nursery in Phoenix.

 Many milkweeds grow easily from seed. Some of the milkweeds listed above are available at  Butterfly Encounters. In addition there are two non-native milkweed species from Africa that grow well here in the Phoenix area: Swan Plant, Asclepias fruticosa and Goose Plant, Asclepias Physocarpa. If you make the decision to grow non-native milkweeds, be sure to always grow natives also. Seasoned butterfly gardeners find natives withstand our desert climate extremes most successfully.

Monarchs need milkweed, and if you provide it for them, they will find it. It's a little work on your part, but when they reward you with their presence, you'll find it was well worth the effort.

Tuesday, October 4, 2011

Monarch Migration in Phoenix

I didn't know that she came but found the fruits of her labor. It was exciting to see the first male monarch butterfly visit my garden in early September (9/14) and surprising to see a female monarch laying eggs on Arizona Milkweed, Asclepias angustifolia, two days later. Hours later before dinner, my son Brian and I went out to see how many eggs we could find. I didn't see her lay many that morning.

Instead of just eggs, we started finding small second instar monarch caterpillars in the milkweed flowers! Not just a few - they were everywhere. While a female monarch can lay 500 eggs in her life time, predators will affect many and less than 10% will become a new butterfly. Earlier we already planned to bring some of the eggs and caterpillars to a protected environment to give them a better chance for survival. We knew we likely would not find them all. Luckily I already had many kinds of milkweed in one gallon containers as well as others planted in the garden so I could easily move the eggs, caterpillars and milkweed to a mesh hamper to protect them.

I never, ever expected to find so many monarch larvae around my yard! Usually ten to twenty monarch caterpillars are good numbers in our desert gardens. Instead I kept finding more and more larvae wherever I looked in different milkweed patches. Yesterday I tried to get a better grasp on the numbers. There are 50 pupae on this "tree", seven new pupae in the hamper, seven larvae were now making silk pads and there were at least 21 5th instar larvae still on outside milkweed plants.

Yesterday the first six eclosed. Five were females and one male. So a couple of  female monarchs left over 80 eggs in my yard! By using degree days, we figured the first female likely came through the yard on Sunday, September 11, while I was out of town. The second female arrived September 16th. In previous years we didn't see egg-laying until the beginning of October during the time of the peak monarch migration through the Phoenix area.  
So keep your eyes open during this premier time of the monarch migration through the greater Phoenix area! For a time we will likely see breeding and migrating monarchs around town. With the cooler weather heading our way and the winds shifting to a more favorable direction, look for monarchs in the air. Don't forget to look in unusual places, too, for any eggs, larvae or pupae they may leave behind during their short time with us.

You can read more about the status of the monarch migration and population this year on the Monarch Watch Blog by Dr. Chip Taylor. How can you help? Grow milkweed! Start your planting list for the Fall plant sales today.