Bird lady is correct. The numbers overwintering in Mexico this year are down 59% from last year, and the numbers have already decreased 6 out of the past 7 years. The cause is multifactorial, but certainly a large part of the problem is inadequate supplies of milkweed due to large scale use of herbicides by farmers. I plan to expand my butterfly garden to include all of my sunny space (which isn't much). I hope it's not too late and that others will do what they can. Thanks, Birdlady, for bringing this to our attention.

Martha

You need to post this in the Perennials Forum, where one would expect to hear about milkweeds. There are smaller, less "weedy " cultivars available which might be more atteactive to gardeners without a lot of room to spare. Seeds are available in all of the mail order seed houses and plants are pretty common, too.

We live in a rural area, and there is an unused septic field north of our garden that is mostly meadow land with a few "weed" cedar trees. There are some milkweeds there and a few have spread up near my compost piles. When we moved here in the Spring of 2010 there were a lot of migrating Monarchs in my zinnia patch, along with several other species of butterflies and skippers. Some of the Milkweeds had Monarch caterpillars and their remarkable looking chrysalises.

This last year there were only a handful of Monarchs moving through, and apparently they made no use of the Milkweeds. No caterpillars or chrysalises. We had lots of other butterflies in the zinnias, including clouds of Fritillaries. But the Monarchs were almost a "no show". Hopefully it isn't too late for the Monarchs.

Incidentally, if you are handling Milkweeds for any reason, be careful and wear disposable gloves and don't let them touch your face. The wiki article on Milkweed mentions mild dermatitis, but there was a GardenWeb forum discussion indicating much more serious consequences than mild dermatitis. A Google search on milkweed toxicity turns up a lot of "hits".

ZM

Here's a link to the article I read.

Here is a link that might be useful: Mexico Monarchs

Actually the greatest loss of milkweed in the U.S. is from counties mowing the roadsides for weed control. This destorys many times more than farmers keeping milkweed out of their fields.

Hi Kimka,

That agrees with what I have seen around here. There are zero milkweeds in the cultivated fields, and there are some milkweeds along our roadsides.

Last year there were milkweeds growing along our roadside as close as 100 yards from where I am sitting now. Not a lot, but some. I didn't notice any caterpillars or chrysalises on them, either. They did put out a lot of their fluffy airborne seeds, though, so there is hope for them.

In our immediate area, most of the roadside does not get mowed, because there are deep drainage ditches that prevent the mowers that are used here from mowing the ditch area. I have seen the highway department use mowers that are on long extension arms that could mow such inaccessible areas, but they don't use that kind of equipment in this area. So the roadside milkweeds are safe in this area for the time being. If the Monarchs would just use them.

As for those many counties across the country that are mowing the roadsides for weed control, they probably aren't even aware that they are hurting the butterflies. But if butterfly activist groups made them aware, they probably wouldn't "cease and desist" in their mowing. Their argument might be that the safety of the motorists was more important than the butterflies.

There are extensive areas that are not suitable for agricultural use. The wide pathways under cross country high voltage power lines are kept clear of trees for obvious reasons, and the meadow flowers that grow there attract butterflies of many kinds. Perhaps those areas could be deliberately seeded with milkweeds. And perhaps the railroads could be persuaded to join in a Monarch conservation effort.

Kimka, I agree with you totally that the recent decline in Monarchs is not from farmers keeping Milkweeds out of their fields. But I am not sure the recent Monarch decline is due to a recent change in roadside mowing either. At least, I haven't seen a recent change in that. We had a bad drought last year and, in fact, we technically are still in that. Droughts are typically multi-year. Maybe this is another "climate change" thing.

ZM

Zenman,

The almost onsessive mowing of roadsides is not new, but it has had a growing depressive impact on the monarchs. A study was actually done a few years ago when a segment of organic supporters decided it was the farmers, Bt corn and pesticides that were killing off the monarchs.

A university (Iowa State University, I think) survery discovered many times more milkweed was being removed by roadside mowing than was being done by farmers.

Maybe one good impact of budget cuts will be less roadside mowing and letting milkweed stands bloom.

I am hoping we will have a good "stand" of milkweeds in our area this year, and that the Monarchs will make good use of them. I will be watching to see how that plays out. This year I may save some milkweed seeds and try to increase the number of milkweeds in our septic area. I think there may be three or four acres there. I may even experiment with growing some of the more ornamental forms of Asclepias.

ZM

When there is fogging done to kill mosquitoes, that's detrimental as well.

Many roadsides are cleared not only with mowing, but with pesticides also. I've seen this being done in several states.

I haven't seen a monarch butterfly on my property in years .... :( even when i tried planting some asclepias last year, I never saw a single one

And you shouldn't have to plant Asclepias in order to see Monarchs. Monarchs sip nectar from a wide variety of flowers. I have seen many on my zinnias in past years. The Asclepias are their food plants, that they lay eggs on to make caterpillars, chrysalises and eventually new Monarch butterflies. The amazing thing is that the "newborn" Monarchs are born knowing that they need to go to a particular place in Mexico, and how to get there. And their brain is only a little larger than the period at the end of this sentence.

ZM

Well said, ZM. One can also encourage municipal and school gardens to plant for butterflies, for both nectar and host plants.

There are factors in their winter home in Mexico at work as well that are depleting their numbers.

You can follow the migration.