Ask a Naturalist

Coming Soon

A: The short answer is: No! Any plants that have bright showy flowers, like the goldenrods, have evolved to attract third party intermediaries as essential partners in accomplishing their pollination goals. Goldenrod’s abundant bright clusters of tiny golden flowers entice insect visitors, including butterflies, bees, wasps, flies and beetles. A bountiful supply of nectar keeps them coming back. Bees and flies also eat some of the pollen. While visiting goldenrod flowers for food, these insects become unwitting pollen couriers, helping to ensure future generations of goldenrod for their own offspring. Goldenrod pollen is heavy and waxy, so it adheres to the body of a visitor that is attracted to the flowers for a meal. It is not designed for flight, so it is highly unlikely to be picked up by the wind and find its way up your nose. Plants that cause allergies, on the other hand, are generally pollinated by the wind. In late summer and fall, the perpetrators are primarily ragweeds, whose flowers are so inconspicuous you could walk right past without noticing them. Ragweeds have very light, small grains of pollen that are mobile enough to be carried by the wind to another ragweed plant—or maybe up your nose or into your eyes if you are in their paths. Grasses, some trees and other plants share this wind-pollination strategy, and may also cause allergies. It’s worth noting that in spite of their allergy-causing potential, ragweeds have some redeeming qualities. These native plants are the caterpillar food for many species of moths and one butterfly, and birds will eat their seeds. In addition to the value their flowers provide to pollinators, goldenrods offer food and shelter to hundreds of species of insects—some of which may spend the winter in goldenrod stems or rolled up in leaves. This is a good thing, because both the seeds and the over-wintering insects provide a source of winter food for birds. Watch while hungry sparrows, chickadees, goldfinches and even downy woodpeckers forage for protein in the form of an insect meal. — Mary Anne Borge, Preserve naturalist If you would like to learn more about goldenrods, click here to register now for The Amazing Aster Family Part 1: Confusing Yellow Composites, which Mary Anne Borge will present Saturday, Aug. 29 (see below).

Q: What should I be doing now to plan for the late summer and fall?—B.B.

A: The end of July is the perfect time to inventory your garden and make plans to supplement it with plants that will keep the feast going for pollinators and birds—and the show going for you—throughout the remainder of summer and fall.

Although there are aster (Asteraceae) family members blooming throughout the growing season, they are especially prolific from now through early November. There are so many options, including goldenrods, classic asters, sunflowers, coneflowers and more. Here are just a few suggestions for your consideration (with gratuitous editorial comments).

For shade:
• Wreath or blue-stemmed goldenrod (Solidago caesia)
• Zig-zag goldenrod (Solidago flexicaulis)
• White wood aster (Eurybia divaricata)
• Blue wood or heart-leaf aster (Symphyotrichum cordifolium)—blooms late September into November!
Partial shade:
• Thin-leaved sunflower (Helianthus decapetalus)
• Thin-leaved coneflower (Rudbeckia triloba)—blooms into November! Short lived, but reproduces readily through its seeds.
For sun:
• Showy goldenrod (Solidago speciosa)
• New England aster (Symphyotrichum novae-angliae)—a classic!
• Aromatic aster (Symphyotrichum oblongifolium)—bushy, and so many blossoms!
• Helen’s flower or sneezeweed (Helenium autumnale)—just gorgeous!
These are just a few of my favorites, but there are so many more from which to choose. Shop the Preserve’s plant sale to see what speaks to you.

If you would like to learn more about the aster family and its members, we have scheduled two opportunities for online learning as part of our Knowing Native Plants series. Click on each link below for more information and to register:
• The Amazing Aster Family: Confusing Yellow Composites, Aug. 29, 10 am – noon.
• The Amazing Aster Family: Classic Asters and Their Colorful Companions, Sept. 26, 10 am - noon.

– Mary Anne Borge, Preserve naturalist

Q: What should I be doing in the garden in July? – J.K.

A: As little as possible! But there are a few things you could think about doing:

• Make sure that any plants you added this spring are getting enough water. Once they are established, native plants can really hold their own and seldom need watering, but for the first year, they like to get about an inch of rain a week. If local rainfall isn’t sufficient, you may need to supplement.


• You can still plant in summer, just be especially careful to water if there isn’t enough rain. Browse the Preserve’s plant sale to find the perfect complement for your summer garden.


• Check for and remove invasive species before they produce fruit and spread. Canada thistle, Oriental bittersweet, wineberry, multi-flora rose, and mugwort are all easy to pull by hand (with gloves!) when the plants are young. So, get them before they establish a strong root system, after which they are much more difficult to manage. Japanese stilt grass is an annual, so pull, mow or weed whack it by August, before it produces fruit. Depending on the size of the affected area, it is easy to hand pull; this could be a great project for the kids! For more information on invasive species, visit the Preserve’s website: https://bhwp.org/grow/garden-with-natives/invasive-species/


• Start thinking about what you would like to plant for fall. With careful planning, you can have something blooming through early November. More on this in our next Preserve Notes.


• Relax and enjoy the beauty of your native plant garden and all of the butterflies, bees, birds and other animals that it supports.

– Mary Anne Borge, Preserve naturalist

Q: Hello! Very interested in your native plant sale. Would you be able to recommend a few flowering plants to add to my pollinator garden that might be rabbit, groundhog or deer-proof? Thank you! — M.M.

A: Good question! Plants have a love-hate relationship with animals.

A high percentage of plants need to attract animals to help pollinate their flowers and disperse their seeds. In support of these goals, plants produce bright showy flowers and tasty, tempting fruits.

On the other hand, plants want to prevent animals from eating their foliage and flowers, because they want to survive and reproduce. Many plant species have evolved strategies to discourage browsing by herbivores, including mammals and insects.

Some strategies are chemical in nature. For example, mint family members produce a strong fragrance and taste that is repellent to many animals. Other plants produce chemical compounds in their tissues that are bitter or even toxic, taste sensations that are off-putting to most animals. Many plant species have the ability to intensify the production of their deterrent chemicals when they detect damage to their tissues, and may also send a chemical signal to other nearby plants that danger is present so that their neighbors, too, can increase their chemical defenses. Some plant species rely on an unpleasant foliar texture, like hairiness or thorniness, or a latex-like sap that can glue mouthparts together. Some plants combine multiple strategies to discourage herbivores.

Often, plants within a family share a protective strategy. The mint, poppy, dogbane and mustard families all have fairly successful strategies that rely on chemical defenses. Some, but definitely not all, aster family members do also.

The Preserve has developed a list of plants which are good for pollinators and have developed self-preservation strategies. Many of them are available for sale at the Preserve. The list is not exhaustive, but it should get you started. You might want to try others in the families mentioned here. Note that there are no guarantees, and animals may taste a few before learning that a species has a bad effect. Other plants that are deer-resistant but not necessarily pollinator-oriented include grasses, sedges and ferns. Be sure to select plants that are appropriate for your growing conditions. For example, shade plants really do belong in the shade and don’t put plants that like dry soil in a place where the soil is constantly wet.

—Naturalist Mary Anne Borge

Common Name	Scientific Name	Family
Dutchman’s breeches	Dicentra cucullaria	Poppy
Wood poppy	Stylophorum diphyllum	Poppy
Bloodroot	Sanguinaria canadensis	Poppy
Rue Anemone	Thalictrum thalictroides	Buttercup
Wild Columbine	Aquilegia canadensis	Buttercup
Toothwort	Cardamine diphylla	Mustard
Common Milkweed	Asclepias syriaca	Dogbane
Swamp Milkweed	Asclepias incarnata	Dogbane
Butterflyweed	Asclepias tuberosa	Dogbane
Poke milkweed	Asclepias exalta	Dogbane
Indian hemp	Apocynum cannabinum	Dogbane
Wild Bergamot	Monarda fistulosa	Mint
Spotted Horsemint	Monarda puctata	Mint
Short-toothed Mountain Mint	Pycnanthemum muticu	Mint
Hoary Mountain Mint	Pycnanthemum incanum	Mint
Virginia Mountain Mint	Pycnanthemum virginianum	Mint
Narrow-leaved Mountain Mint	Pycnanthemum tenuifolium	Mint
Hairy Wood Mint	Blephilia hirsuta	Mint
Downy Wood Mint	Blephilia ciliata	Mint
Lyre-leaved sage	Salvia lyrata	Mint
Wild Senna	Senna hebecarpa	Pea
Blue False Indigo	Baptisia australis	Pea
White Snakeroot	Ageratina altissima	Aster
Sweet Goldenrod	Solidago odora	Aster
Wrinkle-leaf goldenrod	Solidago rugosa	Aster
Gray goldenrod	Solidago nemoralis	Aster
Virginia goldenstar	Chrysogonum virginianum	Aster
Golden Ragwort	Packera aurea	Aster

Q: Do you have any tips for successfully transplanting trilliums? I have heard they do not transplant well.

A: You should plant trillium in shade or dappled shade, and in rich, moist or average soil. Dig a hole as deep as the pot. Pull the plant out of the pot, loosen the roots, hold it over the hole and gently fill in with soil. Finally, to fend off deer, put a cage over it or spray with a deer repellent. At the Native Plant Nursery here, we use a product called Deer Stopper. It is an organic product that is environmentally safe, biodegradable and non-toxic. It doesn’t need to be re-applied after rain and it lasts four to six weeks. At my home, I use the concentrated form, which is much more economical, and dilute it more than recommended. It also repels rabbits.

—Jean Barrell, BHWP Naturalist

Q: How can I attract more birds, butterflies and bees to my garden?

A: That’s easy! Use more native plants. The most compelling reason to use native plants on your property is that they are essential food for the animals with which they evolved, especially insects such as bees and butterflies, but other insects and birds, too. Fortunately, native plants are also beautiful.

Many people are aware that monarch butterflies (Danaus plexippus) can’t survive without native milkweed plants (Asclepis sp.). What they may not know is that the butterflies can drink nectar from many different plants; it’s their caterpillars that can only digest the leaves of milkweeds. Monarchs are not alone in specializing on a narrow group of related plants as caterpillar food. Most butterflies and moths specialize.

Without the native plants with which they evolved, these species would die out. That would be bad news for birds, too, since insects, especially caterpillars, are an essential part of most birds’ diets.

Bees rely on native plants for both nectar and pollen, an essential source of lipids and protein for them. Some bees specialize on the pollen of a small group of related plants, just as butterflies do. Without their special food, they won’t survive.

In his 2020 book, “Nature’s Best Hope,” Doug Tallamy reports that chickadees need at least 70% of the plants in their territory to be native in order to have enough food—in the form of caterpillars—to successfully raise a family. So, if you want to see more birds, butterflies, bees and other native critters on your property, set a minimum of 70% native plants as your goal.

For more information, visit our website: https://bhwp.org/grow/garden-with-natives/attracting-birds-bees-butterflies/

— Mary Anne Borge, BHWP Naturalist

Q: How can I be sure the native plants I select from the Preserve’s Native Plant Nursery are right for my property’s landscape?

A: We get that question a lot. Which of the nearly 200 native plant species we sell each year are right for you? The answer depends on your landscape’s soil type, moisture and sun conditions. It’s never a good idea to put shade-loving ferns in a dry sunny location, or plants that will only bloom in full sun in the shade. Make sure you are matching plants to your growing conditions. Here are some resources that can help:

https://bhwp.org/grow/garden-with-natives/right-plant-right-place/

https://lambertvillegoeswild.weebly.com/plants.html

https://bhwp.org/grow/garden-with-natives/native-plant-plant-profiles-a-to-z/

Consider your other gardening goals, too, such as having interest throughout all four seasons. You can browse our ‘What’s in Season’ favorites for inspiration: https://bhwp.org/visit/whats-in-season/.

— Mary Anne Borge, BHWP Naturalist

Q: “I have a nannyberry plant with distorted leaves on their tops due to aphids, which I killed. What else should I do?” - A. S.

A: I would remove the wilted leaves by making a clean cut at the next leaf node down from the brown ones. Also, to discourage the return of the aphids, you can spray with Neem oil, insecticidal soap (like Safer Soap), or horticultural oil. You will need to spray the undersides of the leaves as well. It's also possible to wipe the leaves with a mild dish detergent solution every few days.

— Donna Dahringer, Native Plant Nursery Manager

Q: “I have a few locations, between pavers and under a large pine tree, that might be good spots for moss. Could you give me some advice on how to grow it, where to grow it, and how to keep it happy and healthy? I have no clue what type of moss it is. I tried planting elfin thyme a couple of years ago between my pavers and it did not spread much and is not looking great thus far. The moss, on the other hand, seems to be very happy.” – F. C.

“I also have a moss garden, so I do have some experience in trying to nurture it along. And, lucky for both of us, moss thrives from neglect! You just have to have lots of patience. I’m guessing that the poor results with the elfin thyme has to do with shade. Thyme species love sunny, hot weather (they’re all Mediterranean species, after all). If you see any signs of moss, it’s because the location is probably shady enough to favor it. Moss will always move into a shady location where the ground is relatively bare (it is considered a “pioneering species” that moves into a disturbed area before anything else), whether you want it to or not. And whatever kind of moss you’re finding now is the best species of moss to grow there. It knows exactly where it wants to be. I would not get too caught up at this point in finding exactly what species you should be growing.

I have a very long path through my shade garden with widely-spaced stepper stones and moss in between them. After the pavers were put down, the moss was transplanted in chunks from elsewhere on the property, broken into tiny pieces and then pressed into place between the pavers. Water it gently until you can see it taking hold (gentle spring rains during cool weather would be best!). It took probably a year or more, but the moss easily filled in the spaces from that point on. You don’t even need that much moss to transplant. Even tiny pieces will take hold and start growing. Of course, the bigger the pieces you transplant, the faster it will fill in.

So, if you have moss anywhere else in your yard that you can transplant, or if you know anyone who has moss in their yard, just ask if you can have a couple of big chunks. Break it into pieces, and then press it into place where you want it. Keep it gently watered, especially during hot, dry weather. Once established, you do not need to be as concerned about keeping it watered. It will go through dry cycles where it looks almost dead, but once it rains, it will pop right back up with green growth within a few hours.

To speed up the process a bit, the best advice is to lower the pH of the substrate (soil) between the pavers by sprinkling the area lightly with aluminum sulfate crystals. Moss grows best on acidic soils. The moss garden at Bowman’s Hill Wildflower Preserve, as well as my own garden, benefits from an occasional application of aluminum sulfate to keep the pH of the soil lower than what would normally be found in your yard. The product is not entirely benign, so make sure you read the safety data sheet that accompanies the product. Having said that, when used properly (and kept away from any streams or ponds in the area), it is not a dangerous product. But that is for you to decide! You can find it at any garden store.

Lowering the pH of the soil has the added benefit of making the substrate more inhospitable to grassy weeds. Grasses will be the biggest competitor of growing mosses, especially annual bluegrass (Poa annua). You should know that growing mosses across a large area isn’t as easy to keep pristine as you’d think. It is the perfect substrate for growing weed seeds of all kinds, which means a bit of weeding for you, and you should endeavor to keep the area as free of leafy debris that falls on top of it as possible.

There are lots and lots of information online about growing mosses. I’ve given you just the basics here, which, with a bit of patience, will work for you. There are lots of “recipes” for grinding moss up in a blender with buttermilk, then pouring it over bare soil, but I’ve never tried it. Nevertheless, you should try anything that sounds promising to you!

The moss garden in Penn’s Woods at Bowman’s Hill Wildflower Preserve is beautiful at this time of year. I sincerely hope the Preserve will be open very soon so our visitors can see it.”

— Julie Davies, BHWP Naturalist