Goldenrods & asters: Important fall flowers for pollinators

With the fall very clearly upon us, we tend to think more about falling leaves than flowers. Indeed, the big flower boom is ending, with all early-season flowers well past flowering. However, fall is a very important season for many pollinators, which still require food and shelter in preparation for the winter. In this blog, I would like to take a little bit of time to go over the importance of fall resources for pollinators, and what you can do to make sure they are available in your green spaces.

Why is fall special in nature?

The end of summer/fall is a special time for many organisms in our temperate regions. This is usually the last chance these organisms have to gather energy and resources to get ready for the winter. In the case of pollinators that are active during this period, the fall is key for collecting sufficient pollen (=food) for their nests, and for finding appropriate overwintering spaces for the adults and/or the offspring (take a look at this post to learn more about this), all of which will impact survival until the following year/season. If we want to help these pollinators, making sure that these resources are available is the best we can do!

Providing food for pollinators in the fall

Several native plants in our area flower in the fall and act as wonderful resources of pollen and nectar (and more!) for our late-summer/fall pollinators. These plants are easy to grow and once established provide abundant (nutritional) resources for our local insects.

Goldenrods

This group (Solidago spp.) consists of many species which flower in the late summer/fall. These plants are perennials that will create patches once established in an area. For this reason, they are easy to grow, although for this very same reason may usually require a bit of containment, since otherwise, they will easily spread everywhere. If the latter is a problem, plants can be grown in pots, where the containment issue is more easily resolved.

These plants support a large community of many different types of bees (many of which are specialists that can use only specific types of pollen and can be rare), as well as butterflies, flies, and wasps. In fact, more than any other herbaceous plant studied by Fowler/Droege, goldenrod (species in the genus Solidago) supported the most specialist bees (39 species). Importantly, because these plants create tall hollow stems, they can also act as nesting resources for stem-nesting bees. This way, these plants are great fall resources for many of our pollinators.

flowering goldenrod mixed with other asteraceae flowers
Goldenrods develop numerous flowers that provide support to a very large number and diversity of pollinators. In this picture, goldenrods stand out of a background of other yellow Asteraceae in a home garden. Photo: A. Espíndola

Two easy-to-grow species that one can find in several native nurseries are the tall goldenrod (Solidago altissima) and Canada goldenrod (Solidago canadensis). Both species have long stems that end with many yellow inflorescences. Both of them flower in the late summer and fall and can be easily grown in green spaces, especially drier sites that are exposed to the sun. As said before, although these plants are great pollinator magnets and resources, they tend to spread readily, so, unless that is wanted, they require some control once they start spreading in an area.

Asters

Asters are another group of plants native to our region that acts as a great pollinator resource in the fall. These plants are also perennials and can be small or become shrub-like, depending on the species. Unlike the goldenrods we were talking about just above, these plants tend to display a larger variety of floral coloration, with flowers going from white, to pink, and purple, depending on the species. Like goldenrods, these plants provide both food and nesting sites to many pollinators. Their flowers attract a very large variety of pollinators (bees, butterflies, flies, beetles, wasps) during a time when there is little else to feed on. The flowers of these plants are also known to support specialist and often rare bees, which depend strongly on its pollen for survival, as well as many butterflies, including Monarchs. Their stems are also great sites for stem-nesting bees. Finally, their leaves support the larvae of many local butterflies.

purple flowers of new england aster and a monarch butterfly
New England asters can be obtained from native plant nurseries and are able to support a very large diversity of pollinators, including rare and specialist bees, as well as adults and larvae of many butterflies. In this picture, we can see a Monarch adult feeding on the characteristic purple/blue flowers. Photo: Glenn Marsh

A lovely species that can be grown in our green spaces and provides hundreds of blue/purple flowers is the New England aster (Symphyotrichum novae-angliae). This perennial herbaceous plant can be obtained from nurseries and will grow three to six feet tall in the summer (but it can be cut back in mid-summer if you want to keep it shorter). The plant requires at least some sun and does well in a variety of soils we find in Maryland. I love watching the lovely cute flowers, and all the activity they attract. This is really one of my personal fall garden highlights!

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!

Deciphering plant tags: annuals, perennials and biennials

Do you remember the first time you went to a garden center? All those colors. All those plants. All those fancy tags with gobbledygook. Help! Plant terminology can vex everyone, even plant geeks. So let me give you the lowdown on some terms that flummox newbies and pros alike.  

The first thing you need to know is that for plants, it’s all about sex. Their number one priority is to make more of themselves. So they are committed to growing robustly to make flowers and seeds. How they get there is different. So we use words like annual, perennial, and biennial. These often confuse folks. Which one do I want? How do they work? What’s the best deal?

It’s all about a plant’s life cycle. Annuals live for a year. Perennials live longer. And biennials take two years to complete their life cycle. Annuals are especially driven to produce seeds because they only have one year to do so. So they push out flowers like mad to make more seeds.

Tithonia – an annual flower. Photo by Marie Bikle.

Annuals’ key selling point: color throughout the growing season. That’s why they are the darlings of container gardens, a blessing for filling gaps and ideal for a sweep of long-lasting color.  

Annuals are less expensive since they last only one season, dying with the first frosts. You can save seeds and replant them, but few do. Some come back from dropped seeds, but that’s rare. 

The downside to annuals is the need to replant them every year. So the cost savings may not be there in the long run and you spend much more time planting. 

In gardens, geraniums, begonias, pansies, marigolds, zinnias, petunias, and snapdragons are commonly treated as annuals.

Perennials are one and done, planted once and persisting for years. Most die to the ground with cold weather, but come back again from their roots, bulbs, or tubers. Most perennials bloom for about a month, but some bloom 2 or 3 times a season if deadheaded. So you don’t get the long flowering time of annuals, but they return year after year.

Perennials cost more but don’t need to be replanted. Plus, they give a different look to your garden throughout the growing season with myriad colors and forms. Perennial gardens have spring, summer, and fall wardrobes. They also are the gift that keeps giving, since you get free plants by dividing perennials every few years. This mitigates their initial higher price tags.  

There are hundreds of perennials including coneflowers, lavender, coral bells, coreopsis, columbine, bee balm, phlox, asters, and goldenrod.  

Biennials flower in their second season. They push out leaves the first year, then flower, make seeds and die in their second year. Hollyhock, foxglove and Sweet William are common biennials. Some biennials reliably reseed so they act like perennials with new plants coming from dropped seeds. Hollyhocks are notorious for rewarding growers year after year.   

I hope I’ve simplified some plant tag terms and made it easier for you to pick what’s right for you – and your gardens – on your next visit to a garden center. 

By Annette Cormany, Principal Agent Associate and Master Gardener Coordinator, Washington County, University of Maryland Extension. This article was previously published by Herald-Mail Media. Read more by Annette.

This article was previously published by Herald-Mail Media.

Helping pollinators in small green spaces

Spring is almost almost aaaaaalmost here, and if you’re like me, you have already started visualizing what flowers will grow where and what pollinators you’ll need to keep an eye out for. Unlike in other posts, where we talked about how to help pollinators in large spaces, today we’ll talk about how to help them in very small yards, balconies, porches, or other small spaces.

small garden in front of a town home
Having a small yard is no reason to not help pollinators. Small yards can be great spaces to support them! Photo: G. Cripezzi.

Small yards

If you have access to a small yard, plenty of opportunities are available! Of course, you will not be able to plant lots of large plants, but that doesn’t mean you cannot plant anything. When offered little space, you can use not just the horizontal, but also the vertical space. While it is possible to cover the ground with a mix of perennials and annuals, there are also possibilities of installing trellises on which flowering vines can grow.

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Wild ginger spices up the Maryland spring

As a pollination biologist, I have the immense privilege of studying really cool plants who trick their pollinators in fancy and incredible ways, and I tend to be naturally attracted to flowers that may not be super showy to most (but are among some of the most mind-blowing things in nature). These flowers are such a wonderful thing in their own right, and in this post I want to do them justice. Because it’s spring and some of these are starting to point their noses out of the ground, in today’s post I would like to (re)introduce you to a plant you may be familiar with, but that I hope after today you will get to look at with new amazed eyes (in case you don’t already 😉 ). Come with me and let’s chat a bit about the wonderful hidden queen of our forests: the wild ginger!

Is wild ginger, ginger?

The short answer is no. While ginger (the plant we eat) is native to Southeast Asia, wild ginger (Asarum canadense) is native to right here, and more specifically to the deciduous forests of Eastern North America. In case you are not familiar with the plant, it belongs to the family of birthworts, which have really interesting ways of interacting with their pollinators. Unlike other birthworts that tend to have flowers that hang in the air from the plant, wild gingers are very “shy” and the whole plant is restricted to the ground level.

Wild ginger is starting to peek out their leaves right now. Once the leaves are fully grown, they get their characteristic heart-shape and can create nice mats to cover the ground. Photos: A. Espíndola; threelark.

The plant is perennial (it lives for several seasons) and exits dormancy in the early spring when its heart-shaped and fuzzy leaves start to unfurl and emerge from the ground. Eventually, the plant becomes a little mat and over time it creates colonies. This is a reason why wild ginger can be a great groundcover plant to use under trees or in shadier and humid parts of one’s yard (see here for how to do this).

Wild ginger is cool – The flowers!

Unlike other birthworts, wild ginger holds its flowers close and parallel to the ground. Wild ginger’s flowers are not showy, being of dark brown and not very large. These flowers are engaged in mimicry pollination, meaning that “disguise” as something else (here, fungi), to trick pollinators into doing something they don’t necessarily want to do. In the case of wild ginger, the flowers are held low to the ground and close to the base of the stems.

Wild ginger flowers are displayed on the ground, at the base of the fuzzy stems. Being dark and close to the ground helps them lure their pollinators, small flies that feed on decaying matter. Photo: A. Carlson.

Wild ginger flowers are dark, particularly moist, and produce specific odors that attract small flies that feed on decaying matter. The tricking consists in making the flies enter the flowers to lay eggs in what the flies consider is fungi (their egg laying sites). While doing this, the flies contact the pollen-bearing structures, and while visiting different flowers, they cross-pollinate them. In this case, we talk about antagonistic interactions between the plants and their pollinators because the interaction does not benefit both partners. In fact, here the plants have the upper hand, and the flies simply loose their eggs to the plant since their larvae can’t feed on the floral tissues. If this is not sufficient to amaze you, keep reading; it gets better!

Wild ginger is cool – The seeds!

After pollination, the flower ovules grow into seeds. Unlike seeds in most plants, wild ginger seeds have a special “addition”. Indeed, the seeds have attached a special extension (called an elaiosome) that is particularly rich in lipids and proteins. This structure makes the seeds very attractive to ants, who collect the seeds, carry them away from the plant, and, after having consumed the elaiosome, discard the seed. By doing this, the seeds can get dispersed farther away from the mother plant, and the population can slowly grow and expand. Isn’t that super neat????!!!

The seeds of wild ginger have a special nutrient-rich body called elaiosome, which is a delicatessen for ants. This allows the plant to use ants to disperse their seeds. The shiny brown (left) and yellow (right) bodies attached to the seeds are the elaiosomes (arrows). Photos: Sid Vogelpohl, Arkansas Native Plants Society; B. Patterson.

Wild ginger as a human ally

Wild ginger was and is still well known to Native Americans of Eastern North America, and it is very likely that they were the ones who showed the European colonists how to use it. Among the Native names still known for this plant is namepin (see here to learn how to say it), which means “plant of small tubers”. Even though it is hard to find the original local names for Maryland tribes, we know that the roots of the plant were used to treat fever and coughs by Cherokees, Iroquois, and Rappahannocks, and that it is very likely that most of the tribes and bands of Maryland (e.g. Shawnee, Piscataway, Pocomoke, Assateague, Nause-Waiwash, Accohannock) use(d) it as well because the plant was and is abundantly present in the area.

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

New! 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!

Some plants are not cool, skunk cabbage heats up

IMG_3725-eastern skunk cabbage at pine hole bogEastern skunk cabbage at pine hole bog by dreamexplorer is licensed under CC BY-NC-SA 2.0

The middle of the winter may seem like an odd moment to think about flowers. In fact, if I look out my window, I can barely see the ground, with most of it covered in snow or ice. So, flowers and all the greenery of spring and summer seem like something that happened in another world which today seems sooooo far away! There are some flowers, however, that defy some of these rules of low temperatures and do a revolution in nature (OK, maybe not a revolution, but still…). In today’s post, and although surrounded by ice and snow, I invite you to join me and warm up using the heat that some plants produce, since we’ll be talking about heat-producing plants!

Really?! Can plants produce heat?

The short answer is yes, which is super cool in itself. The long answer is yes, but let me tell you how, and what are the advantages of producing heat (and why not all plants do it).

The production of heat in plants is relatively rare, and this feature is found mostly in plants considered to have evolved a long time ago from an ancestor to most living plants. Today, heat production in plants is restricted to groups associated mostly with tropical and subtropical environments, such as water lilies, aroids, palms, and birthworts.

Unlike what we may expect, heat production in these groups has not evolved to keep the plant alive, but rather to help the plant reproduce. In these groups, heat production is associated with floral maturation and in particular to pollinator attraction. In these cases, different parts of the flowers increase their metabolism at a specific point in their development, leading to an increase of temperature that in some cases can be extremely noticeable.

In some cases, the heat has been described as a reward for pollination. (Check out this other post for other “special” rewards pollinators get from plants.) This is because it may occur at times of the year (or the day) when the environmental temperatures drop a lot, and when pollinators that visit the flower could benefit from an extra source of heat.

In other cases, heat is known to promote the release and spread of floral odors, which attracts the preferred pollinators. In many cases where heat production is present, it has been observed that plants also display a way to retain the pollinators, such as floral chambers, and in many of those cases the interaction between the plant and its pollinators involves luring and temporarily trapping the pollinators!

plants in the arum family
Some arum family plants (here, the European Arum maculatum) temporarily trap their pollinators. The species shown here displays a chamber in the lower part of its “flower” that is closed by hairs (shown on the right), which let the insects in but makes it hard for them to leave. While the flies are trapped in the chamber, the flowers mature, dropping pollen on the flies. These flies will be released after a while, and some of them will be caught again by another plant, leading to the cross-pollination of the species. Sneaky, sneaky! Photos: A. Espíndola.

While it takes a lot of energy from the plants to produce heat, this usually allows them to flower early in the season while other flowers are not around. This reduces inter-plant competition for pollinators, makes the plants easy to find by pollinators, and increases the chances of having pollen be transferred from one flower to another — all of which increases the number of seeds plants are able to produce.

Our very own heat-producing plant, the Eastern skunk cabbage

Many of you may be familiar with Eastern skunk cabbage (Symplocarpus foetidus), which is among the first plants we see peek out their leaves in the snow or the ice in the early spring. Besides being among the first plants to appear in our region, they are actually also among the first to flower, and that flowering and their pollination are intrinsically related to heat production.

Skunk cabbages belong to a mostly tropical family of plants, the arum family (Araceae). Fortunately to us, some of them do occur also in more temperate regions like ours (another native Araceae from our region is the beautiful Jack-in-the-Pulpit, Arisaema triphyllum). As with many other Araceae (for example, the titan arum), skunk cabbage attracts their pollinators through the production of a very pungent odor, which gives the plant its common name. And like all Araceae, their flowers have a very special shape that allows them to not only produce but also retain heat.

skunk cabbage
The skunk cabbage has a typical arum family flower with a bract that covers the central part of the flower. The central part displays all the reproductive parts. In the picture shown here, it is possible to see the yellow pollen exposed on the flowers of this plant. During flower maturation, the reproductive part heats up, reaching temperatures of over 20˚C (about 70 ˚F)! Center and right images show pictures of the flowers taken using a camera able to measure surface temperature, with a color scale that relates shown colors with temperatures. Photos: left: Janet and Phil; center and right: Onda et al. 2008.

When their flowers start to mature, the “head” of the flowers heats up reaching temperatures of about 70˚F (!!!), even if the surrounding temperatures are below freezing. This heating leads to the release of aromatic odor bouquets, formed mostly by compounds rich in sulfides (thus, the stinky odor). Even though this odor may not be the most attractive to us, it is very much so to the skunk cabbage’s favorite pollinators: small flies and beetles that may be lured by the flower “thinking” it is their favorite food or egg-laying site.

In defense of the plant, though, even though the attraction may be slightly dishonest, the lured pollinators may actually benefit a bit from the visit. While some of them may indeed find laying sites on the plant material, most of them will benefit from the heat received, which especially that early in the season is a much welcome reward! This heat also allows the pollinators to become more active and sometimes even mate within the plant’s flower, which also benefits their own reproduction. Finally, and most importantly for the plant, through this heat release and all the insect movement associated with it, insects passively pollinate the flowers, getting covered in pollen and later transferring it to other equally stinky and warm skunk cabbage flowers. Isn’t this super cool?… I mean, warm?

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

New! Anahí is starting 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!

Delightful Daffodils

Dutch Master Daffodil
‘Dutch Master’ Daffodils in Bloom. Photo: Rachel J. Rhodes

The signs of spring are everywhere from the sounds of spring peepers in the woods to the red hues of maple buds to the yellow blooms of daffodils. The tidbits of spring trickle in like the mist of early morning fog slowly then all at once. As if waking up from a long winter’s nap, you see buds on trees swell or the tiny green stems of bulbs that gently peak through the mulch. The next day, you hear the sounds of spring peepers. Then, all at once, the baby pink blooms of cherry trees are floating like confetti in a ticker-tape parade while crocus shine like amethyst and daffodils glitter like drops of gold in flowerbeds and all of a sudden, spring is here.

daffodils near the woods
Photo: Rachel J. Rhodes

As the daffodils I planted last fall leisurely woke from their long winter’s nap, I began to think about how beautiful they would be in a few weeks with their golden yellow cups and their egg yolk petals, my mind wandered to their name “Daffodil.” When I became a mother, names and the meanings behind them captivated me. As a parent, when you name your child you research everything: the meaning behind a name, where it originated from, the many spellings, and so forth. When the time came to hold my sons for the first time, I was completely and utterly prepared with names that would suit them. The names that would help define them and would help guide them as they traversed through our uncertain world. Did I put too much
weight on a name? Maybe.

As Juliet said to Romeo, “What’s in a name? That which we call a rose by any other name would smell as sweet.” There is a great name debate between Daffodils, Narcissus, and Jonquil. Daffodil refers to the common name for the spring-flowering bulbs in the genus Narcissus. Jonquil is the common name for Narcissus jonquilla within the Narcissus genus. To avoid any ambiguity, you can never go wrong by calling these flowers by their genus name Narcissus.

According to the American Daffodil Society, there are between “40 to 200 different daffodil species, subspecies or varieties of species and over 32,000 registered cultivars (named hybrids) divided among the thirteen divisions of the official classification system.” Daffodils range from the tried and true yellow trumpet to ones with double flowers and clustered flowers, to small cups, and ones with open cups. Flower colors come in an array of white to yellow to orange. There are even some with splashes of pink.

daffodil in bloom
Photo: Rachel J. Rhodes

Daffodils are hardy spring-flowering perennial bulbs that should return year after year. During blooming, they require generous amounts of water. After blooming, always deadhead the spent flowers. Even though daffodil foliage can get unruly, allow the leaves to remain for at least six weeks. You will see people braid or tie the leaves together with rubber bands. This timely endeavor results in the leaves manufacturing smaller amounts of food for the bulb, which in turn results in smaller blooms the following year. After the allotted six weeks have passed, you may remove the leaves.

For Maryland’s hardiness zones, plant daffodils in the fall (from late September to late November). The soil needs to be cool but the ground should still be workable and not frozen. Picking out bulbs is just like picking out the perfect apple. You want a bulb that is firm without blemishes. Bulbs should never be soft, damaged or moldy.

Daffodils are an easy dependable flower that is ideal for the beginning gardener. Don’t forget to pick some up in the fall for your garden!

By Rachel J. Rhodes, Master Gardener Coordinator, Queen Anne’s County, Maryland, University of Maryland Extension. Follow the Queen Anne’s County Master Gardeners on Facebook. Visit the UME Master Gardener webpage to find Master Gardener events and services in your county/city.

Helen’s flower hails pollinators

common sneezeweed flowers
Helenium autumnale. Photo: Beverly Turner, Jackson Minnesota, Bugwood.org

Helen’s flower is an underdog when it comes to native plants. It is not as well known or as popular as butterfly milkweed, bee balm, or black-eyed Susans — but perhaps it’s time for its day in the sun. It makes a nice addition to a pollinator garden.

Helenium autumnale is the species name of this North American native perennial plant. It goes by the (somewhat unfortunate) name of “common sneezeweed” because dried parts of the plant were formerly used for making snuff to induce sneezing. As an ornamental garden plant, it is not known to prompt sneezes from pollen dispersal (it relies on insects for pollination) and I prefer to address it by its lovelier common name, Helen’s flower… or just plain Helenium.

Wild Helenium autumnale boasts cheerful yellow button-like flowers tended by a skirt of turned-down petals in late summer to fall. Its natural habitat in Maryland includes swamps and moist riverbanks, so in your garden, it will like a location where it has some regular soil moisture. It can grow in full sun or partial shade and stretches in height from 2 to 5 feet tall. The flowers support a variety of pollinators such as bees, wasps, syrphid flies, butterflies, and beetles.

A wide variety of cultivars of Helenium are now available. They range in color from bright canary yellow to orange and crimson and various combinations in between. Many of the cultivars tolerate drier soil and have a more compact habit.

Mt. Cuba Center in Delaware conducted field trials of 44 Helenium species and cultivars from 2017 to 2019. They evaluated plants for their habit, vigor, disease resistance, floral display, and pollinator visits.

helenium flowers in a garde
Helenium flowers in a garden, “The warm glow of early Autumn” by hehaden, Flickr

Given the high interest in pollinator gardens right now, I was curious about their observations of pollinator visits in particular.

The native Helenium autumnale had the most observed pollinator visits (162), while the cultivar H. ‘Zimbelstern’ came in second (151). Both of these had excellent powdery mildew resistance as well. Other cultivars such as Helenium autumnale ‘Can Can’ and H. ‘Tijuana Brass’ also had excellent ratings for these two characteristics. The best performers in the study overall (considering all the characteristics evaluated) were ‘Kanaria’, ‘Zimbelstern’, and ‘Can Can.’

The native Helenium autumnale had the most observed pollinator visits (162), while the cultivar H. ‘Zimbelstern’ came in second (151).

For all the details and results of the evaluation, read the report online.  

If you plan to start (or add to) a pollinator garden this spring, do consider adding Helen’s flower if you have a moist site in full sun or partial shade. Mt. Cuba’s report provides good information on plant care, including staking and pruning tips and recommendations for managing the two most common diseases — powdery mildew and aster yellows.

To purchase plants, check the Maryland Native Plant Society’s website for spring native plant sales and nursery sources.

Visit the Home & Garden Information Center website for additional resources on native plants and gardening for pollinators.

By Christa K. Carignan, Coordinator, Digital Horticulture Education, University of Maryland Extension Home & Garden Information Center. Read additional posts by Christa.