News Categories: Mercer Botanic Gardens

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.

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:

www.monarchwatch.org

www.monarchgateway.org

www.saveourmonarchs.org

www.monarchbutterflyusa.com.

(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.

If you’ve ever rested on a bench or taken shade under an arbor at Mercer Botanic Gardens, chances are it’s the work of a Boy Scout. Ever since Arthur Eldred earned the first service award in 1912, Boy Scout projects – from benches and trails to birdhouses and boardwalks – have transformed parks throughout the country.

Today, Mercer has more Boy Scout volunteer opportunities than ever. In fact, Scout groups with the Boy Scouts of America recently restored more than 50 benches damaged by floodwaters from Hurricane Harvey to earn their Eagle Scout Award, the highest achievement the organization offers.

“In the past few months, we’ve had at least four separate Eagle Scout groups working on site, mostly on the weekends,” said Mercer Park Manager Tyler McAndrews. “We provided the stain and varnish, while they brought sanders, sandpaper, and the muscle. The only benches left to be refinished are in the Storey Lake area, and those will be a future project.”

McAndrews said Mercer has several new projects planned for interested Scouts.

“For our next project, we will make up to 60 new tables for the greenhouse area,” he said. “We already have five groups ready to go once we have all the materials collected. Each group will be able to complete eight to 10 tables.”

After the greenhouse tables are complete, McAndrews said Scouts can volunteer to restore Mercer’s iron fencing and brick walking paths.

To get started on a project at Mercer, Scouts need to schedule a meeting with Mercer’s park manager.

“We sit down and talk about what kinds of projects are needed at Mercer,” said McAndrews. “From that point, the Scout makes up a project outline. When both organizations approve the project, we can schedule a project start date.”

Barb Sullivan, a Mercer volunteer and mother of two Eagle Scouts, agrees.

“There is plenty to do at Mercer and several projects that require leadership, organization, and project management,” said Sullivan. “Eagle Scouts encompass all of those qualities in all they do. It’s the idea, the planning, the acquisition of materials, and leading fellow Scouts, family members, and friends to accomplish their goal. It’s a total win/win for the Scouts and the community.”

Some of Mercer’s busiest residents recently received some much-needed assistance.

Volunteers Roger Nelson and Jerry Maxwell, owner of Maxwell Family Bees, added a new honey storage box to Mercer’s beehive just in time for the fall nectar season. The additional box will allow the bees to store more honey as plants ramp up nectar production.

“During the summer, nectar and pollen are in short supply, and the queen’s egg production is reduced,” said Maxwell. “So the bees are on standby waiting for the fall nectar flow to begin.”

Visitors will have a chance to view the honeybee hive when Mercer’s Creekside Ramble opens next year. In the meantime, plant lovers can take pleasure in knowing that some of nature’s busiest gardeners are helping Mercer’s gardens thrive! These little creatures make big contributions by pollinating Mercer’s local native flora and agricultural crops, as well as producing honey and beeswax for harvest.

Wondering how a beehive works? Let’s explore one of the most common backyard beehives, a Langstroth hive.

This multilevel bee high-rise features removable boxes containing vertically hung frames for easy honey access and an inner cover and roof to provide weather protection. The queen always claims the bottom box as her brood chamber. The remaining boxes may be used for honey storage.

Similar to a pantry, each box and frame set, called a honey super, is used for food storage. Bees build honeycomb onto each frame and fill the honeycomb with honey. A single hive may contain one or more supers stacked upon each other, depending on honey flow. When honey production is strong, a hive can fill a super in as little as a week, though it typically takes a little longer.

So how do bees convert nectar into honey? Local bees repeatedly ingest and regurgitate the fluid until it thickens enough for the final bee to deposit it into the honeycomb. Once the honeycomb is full of thickened honey, the bees will cap the comb with beeswax, and the beekeeper can harvest the honey.

Beekeepers typically remove honey supers in the fall after the final harvest of the year to prevent excess honey from crystallizing and to preserve the honeycomb.

Bees don’t hibernate in the winter, so some winter bee care is needed. Because the bees cannot venture out for food, beekeepers should leave the brood box and at least one honey box to sustain the bees through the winter.