We asked you to send us your nature questions. Here are the full responses from our Naturalists.
June 11th, 2020 – Critter-proof Gardens
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|
|Rue Anemone||Thalictrum thalictroides||Buttercup|
|Wild Columbine||Aquilegia canadensis||Buttercup|
|Common Milkweed||Asclepias syriaca||Dogbane|
|Swamp Milkweed||Asclepias incarnata||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|
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/ To get a copy of Tallamy’s book, see below.
— Mary Anne Borge, BHWP Naturalist
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:
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
A: Dear 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
A: Dear 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