News Categories: Mercer Botanic Gardens

14 Jan
By: Communications 0

Name That Flower: February 2020

This graceful shrub grows up to 7 feet tall and has pointed narrow leaves 4 to 9 inches long. The white fragrant flowers appear in cascades around Thanksgiving and continue to bloom through spring.

A native of China and Southeast Asia, this plant is best suited for well-drained soil and partially shaded gardens protected from high winds and late afternoon sun. The shrub should be planted in fertile soil to avoid pests and disease.

Reveal: Glory-Bower (Clerodendrum wallichii ‘White’) in the verbena family.

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14 Jan
By: Communications 0

Revel in the Rose

From Guns N’ Roses and Orson Welles to Shakespeare, roses have captivated and entranced us for centuries.

A symbol of hope, this prominent flower represents new beginnings, balance, and love. In ancient Greece, the rose was closely associated with the goddess Aphrodite. In the Illiad, Aphrodite protects the body of Hector using the “immortal oil of the rose,” and the Greek lyric poet Ibycus praises a beautiful youth by saying that Aphrodite nursed him “among rose blossoms.”

Wild rose bushes grew on hillsides of the island of Crete thousands of years before Christ’s birth. Roses and images of roses have also been found in the tombs of ancient Egyptians.

Historians believe the Chinese and Egyptians first cultivated roses approximately 5,000 years ago by selecting plants based on flower color. Early Americans also held roses in high esteem and gathered regional rose species for food and medicinal purposes. Grown organically, the flower petals can be added to salads and tea for color and flavor. High in vitamin C, rose hips are valued for their nutritive and tonic qualities and used to make jelly and meat glazes.

Rose gardening gained prominence near the end of the Middle Ages because of the flowers’ use in the elaborate gardens cultivated by royalty and wealthy households. Since then, roses have only grown in popularity, popping up in household gardens, traffic medians, and commercial landscapes across the nation.

The ideal time to plant roses is October through early April, when it’s not too hot to stress the plant. Heavy clay soil should be amended with organic matter and sand for better drainage. This will encourage moisture and air in the soil for stronger roots, stems, and flowers. Roses are heavy feeders, so fertilize if you want blossoms. Rose trimming in Houston is usually done in mid-February. Remove the smaller, interior twigs first and then shape to the desired height in your garden. If the roses have grown vigorously over the summer, another trimming in early September is recommended.

Rich in beauty and history, the rose collection at Mercer continues to flourish. The Shakespeare Garden features three small shrub roses – “Martha Gonzales,” a deep red flowering shrub rose with fern-like foliage; “Republic of Texas,” which is a yellow petite rose; and “Sweet Pea,” a shrub rose with dark pink blossoms. Along the Remembrance Walk, find a yellow “Lady Banksia” on a swing arbor blooming in spring. Look for the ”Peggy Martin” rose, dubbed the Katrina rose after surviving Hurricane Katrina, in the Herb Garden.

Several plantings of white roses were installed recently in the Formal Garden near the water wall. These are upright shrubs that bloom throughout the year.

The Healing Garden at Mercer offers hope to people affected by natural disasters. It is adorned with pink Drift roses and white Iceberg roses to signify new beginnings along with a red Valentine rose for love. An expansion of Mercer’s rose collection is slated for this fall.

If you enjoy growing roses and would like to help in the gardens at Mercer, the March Mart Rose Committee meets on Monday mornings.


“What’s in a name? That which we call a rose by any other name would smell as sweet.”
-William Shakespeare

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14 Jan
By: Communications 0

Top Gardening Trends for 2020

From the victory gardens of World War II to the manicured, mid-century modern gardens of the 1950s, the biggest gardening trends often reflect our hopes, dreams, and lifestyles – and the 2020 trends are no different.

After generations of heavy pesticide use, finicky exotics, and sprawling lawns requiring significant water use, Americans are embracing environmentalism, conservation, and healthy lifestyles.

As a result, today’s gardens are often mixed-use beds featuring a blend of hardy natives that can withstand drought and flooding, pollinator host plants, and ornamental edibles. Read more below to learn more about some of this year’s top gardening trends.

Themed Gardens

Trends come and go, but themed gardens will never go out of style. With warmer weather on the way, moon gardens are making a comeback. Dating back centuries, moon gardens include groupings of night-blooming and reflective plants to create spaces that glow in the moonlight.

“People are looking to extend their time outdoors by making the garden more inviting after dark,” said Mercer Greenhouse Manager Jacob Martin. “Others prefer the clean, formal look of all white flowers.”

To bring the trend to your landscape, look for plants with white blooms, variegated foliage, and silver or white leaves. Add soft, warm lighting to spotlight unique plants in the landscape paired with smaller pathway lights to outline the shape of your garden. You can also get ideas for your moon garden by visiting Mercer’s Formal Garden.

Edible Gardens

With the rise of lifestyle blogs, farmers markets, and Pinterest, Americans are finding creative and attractive ways to incorporate vegetables and edibles into their homes and gardens. Today’s trendiest gardens are both beautiful and edible, featuring ornamental vegetables and flowers.
From window sills to the backyard, edible plants are popping up in more locations than ever, and the trend shows no signs of slowing. In fact, one in three households grow some of their own food, according to a 2014 report by the National Gardening Association.

“Anyone with a yard can bring ornamental plants and edible flowers into the landscape,” said Martin. “These plants look good in flower beds and don’t need protection from critters like many vegetable gardens.”

Winter veggies like cabbage, kale, and Swiss chard add vibrant hues of green, purple, and pink to winter landscapes. Best of all, these leafy greens can be harvested at the end of the season and replaced with spring color.

“Edible flowers are also a good option for gardeners interested in growing their own food while maintaining the traditional look of a landscaped bed,” said Martin. “Flowers like violas, marigolds, and dianthus are beautiful, tough, and healthy.

“Winter is a good time to grow edible flowers,” he said. “They look great in the landscape and can be used in a variety of dishes.”

Martin advises anyone interested in growing edible flowers to harvest the blossoms early in the morning or by midday for the best flavor. More than just a whimsical garnish, flower petals feature unique flavors that can enhance desserts, salads, and main courses. They can be candied, pressed into cheeses, frozen and served in drinks, or served fresh in salads, he said.

According to Suzzanne Chapman, the Mercer botanical collections curator, modern gardeners are learning that blended gardens are often just as beneficial as they are pretty. Multi-use gardens save space and attract pollinators, which are essential for food production.

Smart plant pairings may even make gardens healthier by repelling pests and eliminating the need for pesticides, especially around edibles. For example, chives and coriander repel aphids, one of the most common garden pests, and marigolds feature sunny blooms that repel many destructive insects.

Visitors to Mercer can view pairings of ornamental vegetables and perennial flowers in the vegetable display garden. Once the veggies mature, the plants are harvested and used for children’s outdoor cooking programs.

“This is a wonderful opportunity to show visitors what you can grow and blend in with garden perennials,” said Chapman. “Mixing veggies with perennials gives you a great chance to add pretty plants and healthy food to your diet.”

Native Plant Gardens

There’s no shortage of reasons why people love gardening with native plants and flowers. They’re attractive, drought tolerant, low maintenance, and beneficial to wildlife. Most importantly, they’re perfect for the lazy gardener.

“We’re seeing more Mercer visitors interested in planting native plants,” said Chapman. “Homeowners want to grow plants for pollinators and wildlife that can adapt to our crazy weather.”

As people become more environmentally conscious, they look for plants that don’t require supplemental watering and expensive pesticides to stay healthy. “Natives are the most forgiving plants,” said Chapman. “They are tough as nails, and many tolerate floods. They look great no matter what.”

Natives have even become popular among commercial growers, popping up in medians and neighborhood gardens across the county.

“Landscaping companies are planting more natives in medians and neighborhood common areas because they can stand the Houston heat and flooding,” said Martin. “Homeowners are seeing the beauty of these native plants, and they want them at home.”

Popular Texas natives include lantanas, muhly grass, live oaks, and Texas sage. For gardeners interested in something a little more exciting than the standard live oak, Martin recommends the Texas ebony tree. “It’s one of our most underrated native trees,” said Martin. “It’s super easy to grow, and it produces lots of blooms for bees each spring.”

Wildscapes and Pollinator Gardens

The declining population of key pollinators like bees and butterflies has many gardeners fighting back by planting pollinator gardens and wildscapes. These low-maintenance gardens often include pollinator host plants that bees, butterflies, and other beneficial wildlife need to survive.

“Pollinator gardens are easier to grow than vegetable gardens, and they attract more wildlife,” said Martin. “It’s a big trend to attract more bees and butterflies. Everyone wants a monarch waystation and backyard wildlife habitat.”

It’s a trend people can feel good about following. As of September 2019, Monarch Watch had 26,573 registered monarch waystation habitats. And with the United States consuming 2.2 million acres a year of monarch and wildlife habitats, establishing a pollinator garden is a trend worth following.

To get started, gardeners should choose a sunny area to plant milkweed and other flowering native plants. Some gardeners even create wildscapes in their backyards, which are landscaped areas that remain untouched most of the year to provide year-round habitat.

Click here to learn how to plant your own pollinator garden.


Perhaps the biggest takeaway is the trend toward multi-use gardens. Gardeners want beauty, but they also want gardens that benefit themselves, pollinators, and wildlife. For more information about gardening, visit Mercer or stop by one of The Mercer Society’s upcoming plant sales to discuss questions with onsite experts.

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30 Oct
By: Communications 0

Name That Flower: Midnight Horror

Native to tropical areas of Asia, this fast-growing tree reaches at least 30 feet tall. The plant only blooms at night and produces a fetid odor attractive to bats and other pollinators. Can you name this plant?

Midnight Horror

Oroxylum indicum

Meet Midnight Horror. The enormous seed pods of this unique plant (Oroxylum indicum) grow nearly 4 feet long. They hang from bare branches and resemble swords. This plant – popular in Asia – features edible leaves, flowers, and fruit.

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30 Oct
By: HCP4 Admin 0

FAQs: Monarchs and Milkweed

It’s no secret that butterflies love milkweed. The long-blooming plant features tight flower clusters packed with nectar, and the leaves are filled with a milky substance that caterpillars adore. But more importantly, monarch butterflies cannot live without it. Adult monarchs seek the plant for its nectar and lay their eggs exclusively on the plant during the warmer months.

Now that fall monarch migration is in full swing, we’ve compiled a list of your top questions about monarchs and milkweed. Learn about pollinator plants, the fall monarch migration, how to tag butterflies, and plenty of other information about these winged beauties below.

Q: The most recognizable form of milkweed in Harris County is the tropical or Mexican milkweed, which features yellow or orange flowers. What other types of milkweed are good for pollinator gardens?

A: About 35 milkweed species are native to Texas, and about half a dozen grow in the Houston area. For monarchs, the healthiest varieties of milkweed include green milkweed (Asclepias viridis), zizotes milkweed (Asclepias oenotheroides), and aquatic milkweed (Asclepias perennis).

Q: I want to grow Texas native milkweed plants from seed. What is the easiest way to gather the seeds?

A: Milkweed seeds aren’t viable if you harvest them too soon. Wait until the milkweed pod starts to open before stripping the seeds from the pod. If you can’t harvest the seeds right away, place a net over the pod to prevent the seeds from blowing away. To strip the fluff from the seeds, place the seeds in a bag with a few coins and shake. The seeds should settle at the bottom of the bag.

Q: Can I plant different milkweed varieties together?

A. Because most milkweed varieties have different growing conditions, gardeners rarely plant them in the same location. For example, green milkweed, which grows in low spots along rural roadways, prefers heavy, occasionally muddy soil, and the zizotes milkweed requires well-drained soil. Aquatic milkweed, as the name implies, grows in wet bottomland areas along the edges of ponds and creeks. Green and zizotes milkweed prefer full sun, and aquatic milkweed tolerates some shade.

Q: I’ve heard something about a parasite called Ophryocystis elektroscirrha and that it infects tropical milkweed. Should I be concerned about this?

A: Ophryocystis elektroscirrha (or OE) is a parasite first discovered more than 20 years ago, but it’s only recently received attention. OE is concentrated in non-migratory monarch populations in the Houston area. The parasite persists in the Houston area because of our mild winters and long-blooming milkweed varieties, such as tropical milkweed (red and orange colored) and native aquatic milkweed. To prevent the parasite from spreading, cut back your tropical milkweed before each spring so that fresh growth will be available for the spring migration. (Most local monarchs raised in the summer and fall are non-migratory.)

Q: Should I remove my tropical milkweed?

A: Growing tropical milkweed is fine, especially in areas with frost. If it doesn’t freeze, be sure to cut back your milkweed before spring.

For more information, check out the resources below:

(Information provided by Mercer Greenhouse Manager Jacob Martin, TMS Grower Brandon Hubbard, and Mercer volunteer Don DuBois)

Milkweed Varieties 


How to Grow Milkweed from Seed

 Want to grow your own milkweed? Check out this step-by-step guide for growing milkweed in the Gulf Coast area, including zizotes milkweed (Asclepias oenotheroides), aquatic milkweed (Asclepias perennis),  butterfly weed (Asclepias tuberosa), and green milkweed (Asclepias viridis).

  • Rinse seeds with water.
  • Fill a resealable bag half full of sand and add just enough water for the sand to hold its shape. The consistency should be like a sandcastle, not too wet or too dry. Make sure to label each bag with the name of the species and the date.
  • Rinse the seeds and evenly spread them into the sand. Before sealing the bag, make sure to remove all air. Store the bag in your refrigerator.
  • Cool the seeds for at least 30 days. Note: Refrigerating seeds is a technique used to simulate the real-world conditions a seed would receive outdoors as winter turns to spring.
  • After at least 30 days, remove the seed bags from the refrigerator and start preparing your planting trays.
  • Fill a seed starting tray with high quality seed-germinating soil like Jolly Gardener soil, which we use at Mercer. (A 72-count cell tray is recommended.)
  • Dump your sand/seed mixture into a strainer and rinse with water until all the sand has been washed off. Only seeds should be left in the strainer.
  • Plant four to five seeds per tray about ¼- to ½-inch deep and lightly cover with soil.
  • Place the cell trays into a warm area or greenhouse. Water the seeds gently and evenly, using a watering wand or mister. Be careful not to displace the seeds with a hard stream of water. The professionals at Mercer use a misting table to water seedlings.
  • Keep the cell trays evenly moist until germination occurs, which should take about four to seven days.
  • After two to three weeks, the seedlings should be about 2 inches tall and ready to transplant.
  • Transplant the seedlings into 4-inch pots filled with high quality potting soil. Plant one cell per 4-inch pot. If there are multiple plants sprouted in one cell, do not try to separate them. The roots are very fragile and will not take well if damaged.

After about one to two months, the seedlings will be ready to plant in the ground.

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