Goldenrods: The Garden Thyme Podcast

goldenrods episode of The Garden Thyme Podcast

Gold and yellow hues are the undeniable colors of autumn. In this episode of The Garden Thyme Podcast, we discuss one of our favorite yellow-blooming perennial plants – goldenrod. With its pretty yellow flowers, long blooming seasons, and high wildlife value, what is not to love about these fantastic native plants? Mikaela also counts down her top pick of goldenrods for different gardens (~17:10). Her goldenrod bloom chart can be found here.

We also have our: 

  • Native Plant of the Month – Pawpaw (Asimina triloba) (~22:45)
  • Bug of the Month – Goldenrod Bunch Gall Midge  (~33:35)
  • Garden Tips of the Month (~39:15)

If you have any garden-related questions, please email us at UMEGardenPodcast@gmail.com or look us up on Facebook.

For more information about the University of Maryland Extension (UME) and these topics, please check out the UME Home and Garden Information Center.

The Garden Thyme Podcast is brought to you by the University of Maryland Extension. Hosts are Mikaela Boley- Senior Agent Associate (Talbot County) for Horticulture, Rachel Rhodes- Agent Associate for Horticulture (Queen Anne’s County), and Emily Zobel-Senior Agent Associate for Agriculture (Dorchester County).

Theme Song: By Jason Inc 

How Are Aquatic Plants Pollinated?

When we think about pollination, we tend to only think about terrestrial plants. However, a large number of plants are not and actually live fully or partially in the water. These plants also need to reproduce, and thus need to have their flowers pollinated to produce seed. How do they do it? In today’s post, I will try to give a (short) answer to that question, using some native plants as examples.

You may recall from previous posts, that flowering plants require pollination to be able to produce seeds and thus reproduce. Since we are terrestrial organisms ourselves, we tend to be more aware of other organisms and processes that share that trait with us, and pollination is no exception. However, there are lots of flowering plants that are completely or partially aquatic, and these plants also require pollination to produce seeds. Depending on the specific requirements of the plants in question, some of them may use different strategies for pollination.

Wind pollination

Many aquatic or semi-aquatic plants depend on wind to transfer pollen to the female reproductive structures. Especially under conditions distant from land, using wind as a means of pollen dispersal can be extremely advantageous. In fact, being distant from land tends to reduce the types and number of animals that can visit the flowers of aquatic plants. By depending more heavily on wind, these plants usually display light and abundant pollen that can be readily blown away and potentially deposited on the stigma of the female counterparts. A global evaluation of this indicated that about a third of all aquatic plants in the world are wind-pollinated.

In Maryland, an aquatic plant known to be wind-pollinated are watershields (Brasenia schreberi). This plant has non-showy flowers that display both anthers and stigmas. In order for the plant to promote cross-pollination (i.e., avoid receiving pollen from its own flowers), the flowers of these plants go through a complex blooming process that spans two days. This process involves on the first day the receptivity of the stigma (the female part that receives the pollen) and on the second day the maturation and release of the pollen grains. When the grains mature, they are swept by the wind and can reach stigmas from other flowers that are at that point going through their first flowering maturation step.

Animal pollination

It has been shown that a large number of aquatic plants are at least partially pollinated by insects or other animals. In fact, as is also the case in terrestrial plants, aquatic plants can sometimes use both wind and animals to transfer pollen, increasing the chances of some pollen eventually reaching the stigma. Animal-pollinated aquatic plants are pollinated by a large variety of organisms, but their identity will depend on the specific place where the plant is growing and the ability of the pollinator to reach the plant and even survive in that environment. For example, while large bees may be able to fly further away from land, smaller insects may mostly visit plants that are close to land.

A special case of insect pollination of a Maryland native is that of the arrow arum or tuckahoe (Peltandra virginica). The species belongs to the Araceae family and displays a stunning pollination system. As is often the case in this family of plants (see also the skunk cabbage example we talked about in a previous post), the maturation of the female and male flowers is linked to the production of specific aromas. In the case of the arrow arum, these smells attract small flies, and in particular individuals of Elachiptera formosa. These flies seek the flowers to mate, feed on pollen, and eventually lay eggs on the plant, making this an example of what is called nursery pollination (the plant receives a pollination service in exchange for providing a brood site for the pollinator). By moving along the flower, these tiny flies move pollen from the anthers to the stigmas. Some of this pollen may come from the same plant, but other pollen may come from a different flower already visited by the flies.

Water pollination

Finally, many aquatic plants display flowers that are either completely submerged or floating on the surface of water. These plants usually use water currents to disperse their pollen. As with wind, this dispersal is very inaccurate, which usually leads to the release of a large amount of pollen. These plants have either pollen that floats on water or remains attached to the anthers which float to the stigma.

aquatic plants with tiny white flowers on the surface of water
The American pondweed is one of our native species that uses water as their means of pollen dispersal. Note the very small white flowers that are placed on the surface of water. Photo: C. Fisher

A very common native from Maryland that displays this type of pollination is the pond- or waterweed (Elodea canadensis). This species native to North America displays flowers that have either anthers or pistils, but not both. The flowers with anthers are often displayed over the water, from where they release the pollen, which lands and then travels on its surface. By moving on the surface of the water, the pollen can reach the slightly submerged stigmas of the pistilate (female) flowers, which are held on flowers that float at the very surface of the water. Because such a dispersal can lead to large pollen loss, pollen release in this species is only done when the wind is light and the water current is low. This promotes a more “controlled” dispersal and increases the chances of the pollen effectively reaching the stigmas.

By Anahí Espíndola, Assistant Professor, Department of Entomology, University of Maryland, College Park. See more posts by Anahí.

Anahí also writes an Extension Blog in Spanish! Check it out here, 
extensionesp.umd.edu, and please share and spread the word to your Spanish-speaking friends and colleagues in Maryland. ¡Bienvenidos a Extensión en Español!

Q&A: Late Bloomers for the Garden

a red-spotted purple butterfly is feeding on nectar from a native Eupatorium plant with white flowers
Red-Spotted Purple butterfly on a native Eupatorium in September. Photo: M. Talabac

Q:  A lot of my new native plant garden beds contain species that bloom in spring and early/mid-summer. What can I add for pollinators that blooms late?

A:  Fortunately, there are numerous late-season nectar sources, though most are sun-loving species. They are very attractive to migrating Monarchs and any other butterfly on the wing in late summer and autumn, plus bees, wasps, beetles, flies, and plenty of other insects. Seed-eating birds also appreciate the food source once the seeds of those plants ripen by the end of the growing season; nature’s bird feeders.

Lots of late-flowering native plants are in the aster family, including: Ironweed (Vernonia); Goldenrods (Solidago and Euthamia); Asters (formerly genus Aster, now named Doellingeria, Eurybia, Ionactis, or Symphyotrichum); Cut-leaved Coneflower (Rudbeckia laciniata); Blazing-star (Liatris); Elephant’s-foot (Elephantopus); Beggarticks (Bidens); Wingstem (Verbesina); Helen’s Flower (Helenium); perennial Sunflowers (Helianthus); Climbing Hempvine (Mikania scandens); and the Eupatorium group (several common names and genera; Eupatorium, Eutrochium, Conoclinium, Ageratina).

Outside of the aster family, you can also consider Rosemallow (Hibiscus), Obedient Plant (Physostegia virginiana), Turtlehead (Chelone), Common Witchhazel (Hamamelis virginiana), Gentian (Gentiana), Tall Phlox (Phlox paniculata), Lobelia (Lobelia), and Flowering Spurge (Euphorbia corollata).

By Miri Talabac, Horticulturist, University of Maryland Extension Home & Garden Information Center. Miri writes the Garden Q&A for The Baltimore Sun and Washington Gardener Magazine. Read more by Miri.

Have a plant or insect question? The University of Maryland Extension has answers! Send your questions and photos to Ask ExtensionOur horticulturists are available to answer your questions online, year-round.

Non-Native Plants Support Non-Native Mosquitoes

It is a common misconception that all mosquitoes feed on blood. Unlike ticks, which require a bloodmeal to progress from one life stage to the next, mosquitoes largely rely on plants throughout their life cycle. Only adult female mosquitoes bloodfeed in order to acquire protein to lay eggs; otherwise, adult mosquitoes feed on plant sugars to gain energy for flying, mating, and metabolic demands. Once those eggs are laid in standing water, mosquitoes hatch as aquatic larvae that eat microbes supported by decaying organic matter, called detritus. This detritus often comprises plant parts like leaves, seeds, and fruits that fall from nearby vegetation into larval habitat. The next life stage before adulthood, the pupa, is non-feeding, so the amount and quality of detritus mosquitoes receive as larvae are crucial. Just like we tell children to drink their milk to grow up to be big and strong, mosquito larvae with plentiful and nutritious resources can reach adulthood faster, grow larger, live longer, and lay more eggs as adults. Yikes! 

life cycle of a Aedes mosquito from adult to egg to larva to pupa
Aedes mosquito life cycle.
Image credit: Centers for Disease Control and Prevention

Leaves may vary drastically in their chemical composition, affecting which microbes they support, how quickly they decay, and what beneficial nutrients or toxic secondary metabolites they release as they decompose. Researchers are still working to identify important traits in a detritus resource base, but a trend has emerged: non-native plants seem to support non-native mosquito populations better than native plants do.

Native species, whether plant, animal, or microbe, are those that occur naturally in the region where they evolved. Over the course of time, these species have adapted to the local environment and developed relationships with other native species. Conversely, non-native species are those which evolved in a different region from that in which they can now be found. A small percent of non-native species establish and spread rapidly throughout their new home, with the potential to harm human well-being, environmental health, and/or economic prosperity. Some researchers speculate that non-native species share certain traits that make them successful invaders. The Asian tiger mosquito, Aedes albopictus, is one of the most successful invaders of the past century, arriving in Texas from Asia in 1985 and reaching us here in Maryland by 1987. The tiger mosquito is capable of spreading viruses such as dengue, West Nile, and zika; it is also a nuisance vector, driving people indoors with its aggressive daytime biting behavior. 

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An Ode to Beebalms, Our Beautiful Biodiversity Magnets

Scarlet beebalm (Monarda didyma). Photo: A. Espíndola

Among the many native plants of North America, there’s one that every summer stuns me with its beauty and its important role in our ecosystems and our lives. In today’s post, I want to share some information about a lovely group of plants local to right here, which can be easily grown in our green spaces, and which one can observe flowering right now: beebalms!

What are beebalms?

Beebalms are a group of plants in the mint family (Lamiaceae) that belong to the genus Monarda. This genus is restricted to North America and includes several species. In Maryland, there are at least four species present, one of which (M. clinopodia, the basil beebalm) is currently listed as requiring conservation actions (listed as Vulnerable). The other three species (M. didyma, M. fistulosa, M. punctata) appear to be relatively common in the region and are easy to grow in our green spaces. All species reach about 2 to 5 feet in height and are great additions to flower beds because of their beauty but also because they act as biodiversity magnets. For example, the genus Monarda has been recognized as supporting at least three rare and specialist bee species in the Eastern USA, and attracting a lot of natural enemies of pests, meaning that providing these floral resources can support the populations of bee species that depend on the pollen of these plants for their nutrition and help us naturally control pests in our green spaces. And last but not least, later in the season their fruits support birds and, if left uncut, their stems offer overwintering spaces for arthropods.

Scarlet beebalm (M. didyma)

This is a perennial species with dark red flowers that bloom during the summer. As for all beebalms, the flower heads are formed by many elongated flowers that harbor abundant nectar. The plant is incredibly attractive to pollinators, acting as a magnet to bees of all sizes, butterflies, and hummingbirds. Besides its great support to pollinators and other arthropods, this species (along with M. fistulosa) has medicinal properties, which have been identified and used since immemorable times by Native Americans. The very name of beebalm is even related to these uses, since the plant can be used to produce poultices that help with skin affections, including bee stings. Preparations of the plant are also traditionally used to help with digestive and respiratory issues. Finally, as for many mint plants, this species is rich in essential oils, which makes it a good one to flavor foods like one would do with oregano and mint. You can learn more about how to grow this species, along with other facts on this USDA information sheet.

a stand of brightly colored red flowers - monarda didyma

Scarlet beebalms display red flower heads that offer abundant nectar to a large variety of vertebrate and invertebrate pollinators. Photos: A. Espíndola, J. Schneid (CC)

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Ants & Termites: The Garden Thyme Podcast

In this month’s episode of The Garden Thyme Podcast, we are talking about two common household pests: ants and termites. We often get questions about these two pests. While both live in colonies and can enter our homes, they have very different lifecycles and social structures. Some of them are nuisance pests, while others can cause damage to our homes.

We also have our: 

  • Native Plant of the Month – Wild mint (Mentha arvensis)– ~ 24:25
  • Bug of the Month –  Golden-backed snipe fly ~ ~28:30
  • Garden Tips of the Month – ~31:30

If you have any garden-related questions, please email us at UMEGardenPodcast@gmail.com or look us up on Facebook. For more information about these topics, please check out the Home and Garden Information Center.

The Garden Thyme Podcast is brought to you by the University of Maryland Extension. Hosts are Mikaela Boley, Senior Agent Associate (Talbot County) for Horticulture; Rachel Rhodes, Agent Associate for Horticulture (Queen Anne’s County); and Emily Zobel, Senior Agent Associate for Agriculture (Dorchester County).

Theme Song: By Jason Inc

Pollination: The Garden Thyme Podcast

The garden thyme podcast episode on pollination and pollinators

In this month’s episode of The Garden Thyme Podcast, we are excited to celebrate National Pollinator Week ( June 19-25, 2023)! A pollinator is any animal that visits flowering plants and moves pollen from flower to flower, which helps plants reproduce, making fruits and seeds. In North America pollinators include bees, butterflies, moths, flower flies, beetles, and wasps. Worldwide, approximately 1,000 plants grown for food, beverages, fibers, and spices need to be pollinated by animals.

We also have our: 

  • Native Plant of the Month – Beardtongues (Penstemon digitalis and P. hirsutus) ~16:40
  • Bug of the Month – Fig wasps (Agaonidae sp.) ~21:18
  • Garden Tips of the Month – ~30:00

If you have any garden-related questions, please email us at UMEGardenPodcast@gmail.com or look us up on Facebook. For more information about these topics, please check out the Home and Garden Information Center.

The Garden Thyme Podcast is brought to you by the University of Maryland Extension. Hosts are Mikaela Boley, Senior Agent Associate (Talbot County) for Horticulture; Rachel Rhodes, Agent Associate for Horticulture (Queen Anne’s County); and Emily Zobel, Senior Agent Associate for Agriculture (Dorchester County).

Theme Song: By Jason Inc