For many Americans, Fourth of July is synonymous with fireworks. But for gardeners, the pyrotechnics start early. That’s because by mid June, spring pastels are already giving way to dazzling color as red, white and blue flowers begin lighting up the summer garden. Continue reading
Daniel Potter freely admits he’s not an expert on monarchs. But as Professor of Entomology at the University of Kentucky, he and his grad students sure love to run experiments. Recently, they completed a two-year study on the likes and dislikes of the popular orange and black butterfly. Now for the first time ever, there’s a roadmap for building the perfect monarch garden.
If you’re reading this post, you’re probably already a monarch fan. The butterflies’ annual migration from Mexico to Canada is one of the most spectacular events worldwide. All told, the tiny insects fly upwards of 2000 miles roundtrip each spring, stopping four times to breed and lay their eggs. They are the only butterfly species to make such a long, two-way migration.
Over the past 25 years, however, there’s been a sharp decline in monarch populations. Part of this is due to a loss of habitat at the butterflies’ overwintering site in Mexico. Activities such as logging, agriculture and urbanization have all taken their toll on the central highland forests that play host to the insects six months out of every year.
But by far the most significant factor driving the decline is the dwindling supply of a plant called milkweed. The native wildflower is the only plant that monarch caterpillars will eat. And without it, the butterflies cannot complete their life cycle, sustain their migration and ultimately, perpetuate their species.
According to the North American Monarch Conservation Plan, we need 1.8 billion milkweed stems to replace those that have been lost to agriculture and urbanization. And to sustain the annual migration, these contributions need to come from all land sectors. This includes farms, roadsides, schools, zoos and rights of way. And it also includes suburban and urban gardens located along the butterflies’ migratory corridor.
Luckily, an initiative called the Monarch Waystation Program is starting to make a crucial difference. Established in 2005, it engages citizens in conservation by providing instruction and materials on how to build and maintain a monarch habitat. The guidelines are simple: Plant two or more milkweed varieties for the caterpillars to feed on, some nectar sources for the adults, and you become part of a national registry. To date, over 6000 Monarch Waystations in 46 states have become part of the effort.
And as it happened, the Waystation Program Registry provided the perfect jumping off point for Potter’s research into monarch butterfly gardens. A quick Google Earth search by his team revealed hundreds of habitats scattered along the butterflies’ northward route. What’s more, they represented every kind of landscape.
As Potter put it, ‘Some were non-structured, others ‘wild’, and still others were surrounded by hardscape or located in open rural areas.’ Below are some aerial shots of a few of them. (Photo courtesy Dr. Daniel Potter.)
What Potter and his team wondered was this – with all of this diversity, could there be certain habitats that were more appealing than others? To find the answer, the group decided to survey 22 citizen-planted Waystations. Below are some key outcomes from their investigation.
Like most species, monarchs use visual cues to zero in on what they’re looking for. And in the butterflies’ case, these ‘search images’ are made up exclusively of milkweed. But as the Registry revealed, not all Waystations are the same. Did monarchs favor certain monarch butterfly gardens over others?
Monarchs from ‘search images’ for milkweed
To find out, the researchers counted larvae and caterpillars for a year in their target Waystations to see if the type of habitat made any measurable difference.
Monarch caterpillar on milkweed leaf
And they discovered that yes, the butterflies exhibited a strong preference. A structured garden, with milkweed surrounded by mulch, attracted three to five times more monarchs.
The takeaway? If you want more monarchs, make it easy for them to find the milkweed to lay their eggs on. Plant it apart from other plants. Even better, surround it with a mulch circle. But make sure to provide other nectar producing plants nearby for the returning adult butterflies to feed on.
Interestingly, the researchers found that gardens with unimpeded north-south access recruited more monarchs. This makes sense since it coincides with the butterflies’ migratory route.
Monarchs prefer gardens with a north-south access
While all milkweed species are suitable for food, not all are equally favored by monarchs. To find out why, the group compared 8 varieties of milkweed all grown in Kentucky and native to the area. They evaluated them as to their suitability for egg-laying as well as their usability as food for monarch caterpillars. And there was a clear preference.
Where they had a choice, monarchs preferred the taller varieties, Swamp, Common and Showy over the smaller varieties like Butterfly weed.
The takeaway? If you want to attract more egg-laying monarchs to your monarch butterfly garden, plant the tall, broadleaf milkweed varieties.
But what about all of the new milkweed cultivars, you say? As it has grown in popularity (mainly due to monarchs), milkweed is now available in many cultivated varieties boasting unusual colors and sizes.
Asclepias Gay Butterflies Mix/White Flower Farm
Not to worry. Potter and his students discovered that monarchs find these cultivars just as attractive as the straight species. But again, go with the bigger varieties if you want more monarchs.
Finally, there’s the case of tropical milkweed, a non-native plant that has exploded in popularity over the past decade. Both gardeners and monarchs love it. But buyer beware. Tropical milkweed is not ‘bad’, per se, but when planted in warm areas of the U.S. it encourages monarchs to stick around longer. It even enables them to winter-breed.
Tropical milkweed, Asclepias curassavica
Research shows, however, that monarchs breeding on tropical milkweed throughout the winter (rather than returning to Mexico) have higher levels of protozoan infection compared to monarchs in the normal migratory cycles. It turns out that migration is key to outrunning these pathogens.
The takeaway? Stick to the tried and true native milkweed species and help the insects keep to their schedule.
To learn more about Daniel Potter and his research into monarchs and other insects, click here for the Dr. Daniel A. Potter Laboratory.
This article was update September 2021.
Bunny Mellon never formally studied landscaping; yet she grew to be one of the most celebrated gardeners in America. Her list of accomplishments is staggering, ranging from installations on family properties in Virginia, Nantucket and Antigua, to private residences in Paris, to the White House Rose Garden. There is much to be learned from her trial-and-error approach to horticulture. And now, a new book entitled Garden Secrets of Bunny Mellon offers a glimpse into how she developed her aesthetic while providing readers with practicable tips on design. Continue reading
When it comes to stunning, early-blooming trees, it’s hard to beat the star magnolia. Every March, it showers the landscape in a flush of bright white. For what it lacks in size, it more than makes up for in stature. I love how the blossoms hang like fallen stars from its smooth, bare branches.
Now, even small gardens can have a magnolia! What’s more, star magnolia is slow-growing, so it won’t overwhelm your landscape. Topping out at a manageable 10 to 15 feet, it makes an excellent specimen tree while also providing a great backdrop to any mixed shrub border.
Yet for all that, the tree’s most valuable asset, in most people’s view, is its early spring blossoms. Typically flowering in early March, the star magnolia is lush with blooms when most other ornamentals are scarcely starting to bud. Moreover, the flowers are fragrant. Each is composed of more than a dozen ribbon-like petals. And some varieties boast as many as 30.
And while star magnolias are typically associated with white flowers, there are also a number of pink varieties. All are magnets for pollinators, which gives your other plants an early start on the season.
But, for those who think star magnolias are all about spring, think again. The little trees offer fall and winter interest as well. In autumn, the foliage turns yellow, then bronze, providing an interesting complement to other fall colors.
And star magnolia’s twiggy, many-branched shape provides great winter interest. Colored a shiny, chestnut brown, the branches contrast handsomely with the tree’s smooth gray trunk, which slowly turns silver with age. As an added plus, the buds, appearing in late winter, are fat and fuzzy, just like pussy willows.
Ready to give star magnolia a try? Below are some the most popular cultivars that offer reliable, low-maintenance early spring color. Deciduous magnolias are best planted when dormant, typically in late fall.
‘Centennial’ produces fragrant, waterlily-shaped blossoms in early to mid spring. The large white flowers often have a pink tinge at the base of the petals.
Magnolia stellata ‘Centennial’
‘Jane Platt’ produces double, scented, pale pink flowers with long, narrow petals in early to mid spring.
Magnolia stellata ‘Jane Platt’
‘Royal Star’ has pale pink buds that open in early spring to pure white flowers. In particular, this cultivar is known for its almost 5-inch (12 cm) wide flowers with up to 30 petals. ‘Royal Star’ blooms later than the species.
Magnolia stellata ‘Royal Star’
‘Rosea’ is a pink-flowered variety. It has a rounded shape and dense bushy habit. This cultivar flowers a month later than the species, or in late April.
Magnolia stellata ‘Rosea’
Star magnolia flowers are vulnerable to damage by late spring frosts, so it’s best to plant the trees in a sheltered spot. While they’ll do fine in full sun, they’ll perform best in morning sun with filtered shade in the afternoon. Generally, the more exposed the location, the earlier the flowers open. Like most plants, star magnolias prefer moist, well-drained soil.
Magnolia stellata really shines when viewed against a dark background. Site it in front of a stand of deep green arborvitae, a yew hedge or even a dark brick house and watch its flowers ‘pop.’ Daffodils with cream or white petals and yellow cups make excellent early-spring companions. Check out Narcissus ‘Sovereign’, ‘Golden Echo’ or the orange-cupped ‘Barrett Browning’ for a dramatic effect.
To see photos of my garden designs, including plant lists, check out my Instagram at carole.herebydesign. I post seasonally from spring through fall.
Sometimes life can seem like a maze, full of twists and turns and lots of dead ends. It’s not always clear how to approach the center. But for those willing to walk its cousin, the labyrinth, there can be true transformation. Some say the process ultimately leads to insights into the circuitous path of life itself. Continue reading
Cool-season flowering plants
In my view, autumn doesn’t have to spell the end of the show in the garden. Fall containers offer countless ways to still enjoy seasonal splashes of color. Moreover, these mini gardens no longer have to be all about flowering kale or mums. With a little ingenuity, you can create autumn planters every bit as beautiful as their lush summer cousins. Continue reading
Long before it became a trending food, flowering kale was a garden star, delivering a pop of color to fall’s graying landscape. The plant is not only prized for its striking foliage but it’s also one of only a few species that thrives in cold weather. Indeed, flowering kale likes cold temperatures so much that it often stays attractive well into winter. I can’t think of a better choice for fall gardens and containers. Continue reading
You would almost believe you’d dropped into a fairy tale. France’s valley of the Dordogne boasts a bucolic green countryside that has long inspired painters, authors and poets. Home to the deep green Dordogne river, tiny rural villages and medieval castles perched high on hilltops, it is also the site of one of the most famous topiary gardens in France, the spectacular Gardens of Eyrignac. Continue reading
It was a perfect, sunny day and the homes were spectacular. This was my first time attending Virginia’s Historic Garden Week, and the Dolley Madison Garden Club’s ‘Centennial Tour’ didn’t disappoint. It was an extra-special event, as it also marked the club’s 100th anniversary. And to commemorate the occasion, two historic residences were open to the public for the very first time. Continue reading
Naturalistic plantings at the Denver Botanic Gardens
If you’re used to order in the garden, naturalistic plantings can seem a bit out of control. But installations such as New York City’s High Line are bringing this new, plant-driven approach more and more into the mainstream. That’s according to award-winning designer Carrie Preston of the Netherland’s Studio TOOP. She spoke recently in Maryland on how to incorporate naturalistic plantings into all types of landscapes. Continue reading
