Cheyenne Garden Gossip

Gardening on the high plains of southeastern Wyoming


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Monarchs and Milkweeds

2019-02 Monarch - dead

Explore the mysteries of monarchs and milkweeds in your backyard

By Barb Gorges

Monarch butterflies are hard to find in Wyoming. This is partly because we have few people looking for them and because of the terrible decline in monarch numbers. I found a dead one last year. I hope this will be the year I see my first live one in my garden.

That one will be descended from a monarch that’s currently wintering in Mexico (not from the group west of the Rockies wintering in California).  It’s the only North American butterfly that must migrate because it can’t survive cold winters like other butterflies.

In spring the generation that wintered in Mexico produces the next generation while on its way north and that one begets another, and so on. After a few months, it may be the fourth generation we finally see here. There are several more generations produced over the summer and the final one makes it all the way back to Mexico in the fall.

Monarchs have been clobbered on both ends of their route. Mexico has established the Monarch Butterfly Biosphere Reserve in the relatively small area they cluster. Here in North America, besides building on and paving over habitat, the problem has been planting herbicide-resistant crops and spraying them with herbicide to kill weeds—which also kills milkweed.

While monarchs feed on nectar from a variety of flowers, they only lay eggs, tiny white dots, on milkweed—it’s the only plant their caterpillars will eat. The good news is that there are about 100 species of milkweed found all along their migration routes. There are 13 species in Wyoming—and four right here in Laramie County.

If you want to join the effort to garden for monarchs, you want to grow our local native flowers. Of course, monarchs are not the only nectar-lovers that will enjoy them.

Two species, Asclepias viridiflora, green milkweed, and A. pumila, plains milkweed, are not seen commercially as seeds or plants. But the other two are quite popular.

2019-02 Asclepias speciosa

Asclepias speciosa, Showy Milkweed, photo by Barb Gorges

Asclepias speciosa, showy milkweed, a perennial, has large round balls of pink florets on stems 2 to 4 feet tall. Its vigorous rhizomes help it spread. I got a few plants from my neighbor who was digging them out of her lawn. But on the other hand, their taproots are sensitive and not all my transplants survived.

I’ve also collected seed from showy milkweed in the unmowed corner of the field where I walk the dog. Seeds are easy to grow if you leave them in the refrigerator for two months to cold stratify or use the winter sowing technique no later than March 1 (https://cheyennegardengossip.wordpress.com/2016/03/21/winter-sowing/).

Plant showy milkweed in full sun for maximum number of flowers. Water it regularly the first summer to get it started. Around the county I see it alongside roads where it gets extra water from runoff when it rains. It is not going to bloom much in a very dry location.

The other local milkweed, Asclepias incarnata, swamp milkweed, I haven’t grown myself yet. Master Gardener Michelle Bohanan assures me that despite its name, it doesn’t need a swamp. Like showy milkweed, it does best with a little more water than just rain to maximize blooms and nectar production. It grows 2-3 feet high, usually with pink flowers, though Michelle has a white variety.

Considering milkweed has been treated as a weed and grows unaided in weedy places, I wouldn’t worry much about fertilizers or compost.

If your showy milkweed gets ugly late in the season, don’t cut it back until there’s nothing left for caterpillars to eat. And even then, the dried plants are useful for catching snow—free winter watering. I cut them back in spring.

All the websites devoted to monarchs say avoid buying plants treated with systemic pesticides. The long-lasting neonicotinoids get in the nectar and poisons the butterfly—and other pollinators. Avoid these herbicide ingredients: Acetamiprid, Clothianidin, Dinotefuran, Imidacloprid, Nitenpyram, Thiacloprid and Thiamethoxam.

Butterflies are also looking for shelter from wind, for sun-warmed rocks and pavement to bask on and for places to puddle on damp sand to get a drink.

The great thing about growing a garden for monarchs is that it also works for bees and birds. But let’s not stop at the garden gate. How about encouraging native flowers along our roads, in corners of fields, in our parks? I’m excited to hear that Nettie Eakes, the head horticulturist at the Cheyenne Botanic Gardens, has plans for more perennials in city beds. Many natives, we hope.


MONARCH WEBSITES

Area milkweed seed sources with growing tips:

Beauty Beyond Belief Wildflower Seed, Boulder, Colorado, https://www.bbbseed.com/

Botanical Interests, Broomfield, Colorado, https://www.botanicalinterests.com/

Western Native Seed, Coaldale, Colorado, http://www.westernnativeseed.com/

Wind River Seed, Manderson, Wyoming, seemed to be out of stock, http://www.windriverseed.com

 

Monarch information

University of Wyoming Biodiversity Institute, Monarchs and Milkweeds, https://www.wyobiodiversity.org

Monarch Joint Venture (government agencies, non-profits, academics), https://monarchjointventure.org

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Ground covers

2017-8 Sweet Woodruff by Barb GorgesPublished Aug. 13, 2017, in the Wyoming Tribune Eagle, “Covers of Color, ground covers good for replacing grass or gravel, and feeding bees”

By Barb Gorges

Gardeners consider ground covers to be short plants that act as living mulch, suppressing weeds and preventing erosion.

Your bluegrass lawn is a ground cover. Because it is so popular, its growing needs are well known. You can easily find someone to grow and mow it for you. Even simpler is growing native grasses—less water and much less mowing [search “Buffalograss” at www.CheyenneGardenGossip.wordpress.com].

However, when I surveyed the Laramie County Master Gardeners for their favorite perennial ground covers, a variety of short, flowering plants were listed requiring various amounts of sun and water.

All have big advantages over mulches like gravel or wood chips. Established ground covers out-compete weeds. Rock and wood chip mulches, on the other hand, eventually fill with weeds. Plants keep the ground around themselves cooler. Rock mulch makes an area hotter. Plants recycle carbon dioxide and make oxygen. Rocks and woodchips don’t.

A blooming ground cover offers more for bees and butterflies than rock, wood or a plain lawn. You can combine plant species in a mosaic, or in what’s being called a tapestry lawn by researchers at the University of Reading in Britain.

And you are in luck, late summer is a great time to find perennial ground covers on sale at local garden centers.

Plant now, a month or two before winter weather sets in, and you should see most of your investment sprout in the spring.

How close together you plant depends on how big a hurry you are in to get an area to fill in.

When comparing hardiness ratings, keep in mind Cheyenne is rated Zone 5, but many local gardeners look for hardier varieties rated down to the colder Zone 4 and even Zone 3.

Stonecrop, Sedum hybridum, is recommended by Catherine Wissner. There are many varieties of these succulents, but this one is only 4 inches high. It produces yellow flowers in late spring and early summer. It needs full sun, low amounts of water (after establishment) and is rated Zone 4.

Birdseye Speedwell, Veronica filiformis, is another of Wissner’s choices. This Zone 3 speedwell is only 2 inches tall. Fast growing, in some climates it can invade turf. Small blue flowers with white centers bloom mid-spring.

2017-08 Turkish Veronica Mary Ann Kamla

Turkish Veronica, by Mary Ann Kamla

Turkish Veronica (or Speedwell), Veronica liwanensis, is one of three kinds of ground covers Martha Mullikin grows between flagstones. They all do well because they get the extra moisture running off the stone. This Zone 4 perennial becomes a blue-flowered carpet 1 to 3 inches tall in spring. It prefers sun with afternoon shade and a drier situation. Linnie Cough said hers blooms for two months. It is a Plant Select variety developed by the Denver Botanic Gardens and Colorado State University for thriving in western gardens.

Woolly Speedwell, Veronica pectinata, is a favorite of Susan Carlson. It is like Turkish Veronica, but the leaves are silvery instead of glossy. Both stay green over the winter.

Woolly Thyme, Thymus lanuginosus, and Lemon Thyme, Thymus citriodorus, are the other two forming mats over the flagstones at Mullikin’s. Both are good to Zone 4. Both like full sun and do well in xeric (dry) conditions. Lemon Thyme has the added benefit of being considered a culinary herb.

Red Creeping Thyme, Thymus praecox ‘Coccineus,’ listed by Tava Collins, is a red-flowering ground cover that doesn’t mind being stepped on a little. A Zone 4, it is drought tolerant once it has been established.

Mullikin is enamored with Dianthus ‘Tiny Rubies,’ Dianthus gratianopolitanus, which forms a 2-inch tall mat of leaves covered in pink flowers mid-spring to mid-summer. It prefers full sun and doesn’t mind the colder temperatures of Zone 3.

Barren Strawberries, Waldsteinia ternata, will remind you of strawberries, but the small yellow flowers (Mullikin has a variety with pink flowers) produce fruit considered inedible by people—no word on whether squirrels like them. A Zone 4, it likes full sun to part shade, and is somewhat drought tolerant.

2017-08 Periwinkle by Barb Gorges

Periwinkle, by Barb Gorges

Small-leaved Periwinkle, Vinca minor, Kathy Shreve said, “can take shade, and will grow under a limbed-up spruce tree if given enough water.” A Zone 4 less than 4 inches high, its periwinkle-blue flowers show up in May and early June. Mine, despite being in deepest shade, still plots to take over the world so I prune it when necessary.

Sweet Woodruff, Galium odorata, is another that does well in shade (it doesn’t like full sun), but I think mine would do better if I watered it more—it might reach the listed height of 6 to 12 inches. A Zone 4, its tiny white, fragrant flowers show up in May. Tava Collins said when it is stepped on or cut (or mowed), you may get the sweet smell of hay.

Hummingbird Trumpet, Epilobium canum ssp garrettii ‘Orange Carpet’ also goes by Zauschneria garrettii. Shreve reports it is a “great xeric ground cover, does not seed around indiscriminately, and hummingbirds really do love the orangey-red flowers. Also, it blooms in late July-August when most everything else has pooped out.” This is precisely when migrating hummingbirds passing through Cheyenne would appreciate it. A Zone 3, it is also a Plant Select variety.

2017-08 Soapwort Saponaria Mary Ann Kamla

Soapwort, by Mary Ann Kamla

Mary Ann Kamla recommended several plants including Creeping Jenny, Lysimachia nummularia, a Zone 3 with yellow flowers mid-summer. Mildly invasive, she keeps it contained with the edge of the patio.

Another that is doing well for Kamla is Soapwort, Saponaria officinalis. A Zone 3 with pink to white flowers, it appreciates water. Its leaves have historically been boiled to make a bubbly liquid soap.

Tava Collins is a fan of Spotted Deadnettle, Lamium maculatum. She grows two varieties: ‘Purple Dragon’ and ‘Pink Chablis,’ the names describing the flower colors. Hers bloom throughout the season, Collins said. The leaves are silvery with green edges. These varieties are Zone 4, but some others aren’t as cold hardy. Cutting back will encourage new blooms. The bumblebees love Lamium, Collins said.

2017-08 Spotted Deadnettle by Barb Gorges

Spotted Deadnettle, by Barb Gorges

Also on Collins’ list: Black Scallop Bugleweed, Ajuga reptens ‘Black Scallop.’  Ajugas are good ground covers in general. This one has leaves that look nearly black when grown in full sun. Early summer it has blue flower spikes. A Zone 3, it can be invasive in the garden.

Richard Steele simply grows clover instead of grass. It’s mowable, takes less water, he says, and it feeds his bees, which provide him with honey.

There are two ground covers I planted this year that Shane Smith, Cheyenne Botanic Gardens director, mentions in his garden tips at www.botanic.org. One is Creeping Phlox, Phlox subulata. A Zone 3, it should have no problem coming back next year, but since it prefers sunnier spots, I’ll see if it its pink and white flowers will develop in the shade.

The other is Snow-in-Summer, Cerastium tomentosum, another Zone 3, with silvery green leaves. Maybe next year it will give me more than one white flower. Patience, patience. Growing perennials is a long-term investment