Monthly Archives: November 2016

A Very Berry Time of Year

‘Tis the season to be berry! Winterberry, that is…

There are some native plants that you grow, not so much for their flowers, or foliage, but for the blazing color of their berries. This is the time of year, in late autumn when the landscape is mostly brown and gray, that the winterberries come alive in the wetlands throughout New England:

Winterberries in full berry bloom along Route 9, Brookfield MA

Winterberries in full berry bloom along Route 9, Brookfield MA

Winterberry (Ilex verticillata) is native to the eastern US, and is our only deciduous native holly. It has become very popular as a landscaping shrub for its fall and winter interest.

Earlier in the fall, winterberries ripen to a bright glossy red, but are visible only as red swabs across a vast fiery canvas:

Winterberry holly at the pond, Garden in the Woods, Framingham, MA

Winterberry holly at the pond, Garden in the Woods, Framingham, MA

It’s winter, when all is replaced with white, that winterberry really shows its colors:

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Birds love the berries too (called drupes), but mostly overwintering birds such as cedar waxwings, robins and bluebirds who don’t migrate. Summertime birds don’t touch the berries because they don’t taste good until later in the year — when a few freeze and thaw cycles seems to make them edible. So thankfully for us, the beautiful red berries usually last through the first of the season snows before they are gobbled up.

Most of the winterberries sold in nurseries are cultivars selected for their compact habit (e.g. ‘Red Sprite’), larger berries (‘Jolly Red’) or even unusual berry coloring (‘Winter Gold’):

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Orange-gold berries on Winterberry ‘Winter Gold’ (in background) at Tower Hill Botanic Garden, Boylston, MA

As a wildlife gardener, I’m concerned that the berries of some winterberry cultivars may not be as attractive to wild birds who rely on fall fruits for survival in early winter. I’ve heard anecdotal evidence that the berries found on wild-grown winterberry species disappear long before the berries found on the cultivars, so I’m curious to see whether this is true in my area. I have ‘Winter Red’ planted on my property, along with straight species nearby, but the berries of all of them are always gone by New Years. It makes sense that local birds might prefer food from local genetic provenance, as indigenous plants and bird species have co-evolved over millennia, and rely on each other’s presence in the landscape. Certainly local herbivores (mostly local insects which are crucial food for nesting birds) are more likely to prefer the locally-grown native winterberry foliage as a food source.

Position your Winterberry shrub within a sight line of a window, so you can enjoy viewing the berries and birds in wintertime!

Position your Winterberry shrub within a sight line of a window, so you can enjoy viewing the berries and birds in wintertime!

So if you’re looking for an eastern US native shrub to plant “for the birds” and  have an area with decent soil moisture and mostly sun, winterberry is an outstanding choice. Don’t forget that as a holly (Ilex), winterberries are dioecious, meaning that in order to produce fruits, female plants need a male winterberry planted nearby blooming at the same time, so that bees and other pollinators can transfer pollen from male to female flowers. Ask for a “male pollinator” at the nursery, and plant it within a bumble bee’s flight distance of your female winterberry (50-100′ or so).

Bumble bees are frequent visitors to winterberry holly flowers, and their pollination services are essential for female plants to produce their fruit “crop”. Susan Pelton photo from https://uconnladybug.wordpress.com/2015/06/23/little-flowers-can-have-a-big-impact/

Bumble bees are frequent visitors to winterberry holly flowers, and their pollination services are essential for female plants to produce their fruit “crop”. Susan Pelton photo from https://uconnladybug.wordpress.com/2015/06/23/little-flowers-can-have-a-big-impact/

Note on Male Winterberries: ‘Southern Gentleman’ is a male clone commonly sold at nurseries, but propagated from southern genetic stock, so not ideal for northern gardens — it’s genetically programmed to bloom at a different time than northern varieties. Ask your native plant society for growers that propagate their plant stock from regionally local genotypes to purchase your winterberry hollies.

This is reprinted from my original article posted in the now defunct Native Plants & Wildlife Gardens blog.

Native Shade Plants for Woodland Buffers (Or..Why To Say No to Free Vinca!)

The exotic (non-native) Japanese Pachysandra (Pachysandra terminalis), Lesser Periwinkle (Vinca minor), English Ivy (Hedera helix) and Wintercreeper (Euonymus fortunei) have long been staples of New England gardens for their shade tolerance and ground covering habit. Go to any garden club sale or plant swap in the spring and you’ll find these plants available by the bucketload — but if you live in the northeast US and have a bit of woods separating your property from your neighbors, think twice before bringing any of these plants home.

Vinca minor forms mats under trees, but can spread into nearby woods if not contained or blocked with edging or walkways. This small wooded buffer in Boston’s suburbs is completely covered with vinca which has crowded out the lady’s slippers, lowbush blueberries and solomon’s seal which once grew here.

Vinca minor forms mats under trees, but can spread into nearby woods if not contained or blocked with edging or walkways. This small wooded buffer in Boston’s suburbs is completely covered with vinca which has crowded out the lady’s slippers, lowbush blueberries and solomon’s seal which once grew here.

Because these plants spread aggressively by their roots or stems, when they are planted adjacent to moist woods in New England, they can quickly spread into the woodlands, choking out anything else that happens to be growing there and threatening unique and fragile woodland plant communities. English ivy and Wintercreeper also climb trees and can eventually kill them (not to mention the damage the  ivy can do to your house if you allow it to climb walls).

And once these plants are established in an area to their liking, good luck getting rid of them if you ever decide you’d like to plant anything else! Pictured below is a small woodland buffer in Sudbury, MA, highly valued by the homeowner for its summertime privacy screening from neighbors. The vinca, pachysandra and English ivy planted decades ago near the house have escaped into the woods and the homeowner is frustrated that the young trees are dying, and that she cannot get seem to get any other plants established here:

This client opted for professional removal of the invasive plants using a mixture of low-impact (non-herbicidal) removal methods and looks forward to establishing a woodland garden with plants such as trilliums, bugbane, wild phlox, baneberry, wild ginger and ferns.

This client opted for professional removal of the invasive plants using a mixture of low-impact (non-herbicidal) removal methods and looks forward to establishing a woodland garden with plants such as trilliums, bugbane, wild phlox, baneberry, wild ginger and ferns.

If you drive around the leafy outskirts of Boston MA, you might be impressed at the established trees, especially in older neighborhoods (more than 50 years old).  Many of the spaces between houses are heavily wooded — in New England, trees don’t need much encouragement to grow. But take a closer look at what else is growing under those trees. You’ll quickly notice those same few species of plants in just about every neighborhood.

You won’t see these plants on New England state invasive plants prohibition lists, simply because they don’t reseed themselves the way invasives such as Asiatic bittersweet do — by birds eating and dispersing their berries far and wide. They spread mostly from being planted in favorable conditions near moist woodlands. As so much of our region is now gobbled up by roads and development, those wooded buffers between homes are often the only wildlife habitat that remains in metropolitan areas of the northeast. Although birds might utilize the trees for their nesting opportunities and insect forage, a buffer taken over by invasives will lack most of the ecological benefits provided by a diverse understory of native woodland plants. For homeowners that understand that their yard plantings have an impact on the wider environment, a little effort to search out appropriate native plants will go a long way towards increasing the biodiversity and wildlife value of suburban yards. Not to mention, the results are much more interesting!

Woodland garden at New England Wild Flower Society’s Garden in the Woods in Framingham, MA.

Woodland garden at New England Wild Flower Society’s Garden in the Woods in Framingham, MA, with rhododendron, wild blue phlox, bloodroot, ferns, solomon’s seal and an abundant layer of leaf litter.

So, if you do border on moist woodlands, what are some “safe” alternative groundcover native plants to look for? Try the beautiful running foamflower (Tiarella cordifolia), which is (mostly) evergreen and forms a thick weed-suppressing mat under trees:

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There is also a native pachysandra called Allegheny Spurge (Pachysandra procumbens) that hails from the southeast US, but grows happily in my zone 5 central Massachusetts garden. It looks a lot like Japanese pachysandra but its leaves are not as glossy:

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Early season foliage of Allegheny spurge is bright and green, and later in the season turns to a mottled pattern. It is not evergreen in my Zone 5 Massachusetts garden.

American Yew (Taxus canadensis) is a native yew that loves the cool, damp shade of New England forests. Unlike its popular Eurasian cousins that are standard as sheared foundation shrubs in the US (T.cuspidata, T. baccata, T. x media), this yew stays low (2-3′) and spreads up to 10′ from its base:

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Canada yew growing along a stream in Spencer, MA. It loves the cool damp microclimate of this forested north-facing valley slope.

Because it’s a deer favorite, wild populations of American Yew are becoming rarer in Massachusetts, as suburbia pushes outwards and deer populations soar out of control. Unlike other conifers, however, American Yew will resprout after being pruned (by deer or hedge-clipper), so if you live where deer populations are somewhat under control (or you are willing to put up deer fencing), the evergreen Canada yew is worth growing to help preserve local populations and genotypes.

Wild ginger (Asarum canadense) is another native that will fill an area in moist shade. It’s growing here at Garden in the Woods along with several types of fern and Allegheny Skullcap (Scutellaria serrata).

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More native eastern ground covers suitable for moist shade include mayapple (Podophyllum peltatum) which typically grows in thick patches under oak trees:

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I don’t believe Japanese pachysandra or Vinca will disappear from our home landscapes any time soon, and admittedly, as long as they are contained, they should not cause much harm. A patch CAN be useful if you have dogs. Our border collie Speck hates the heat of summer and loves to cool off in pachysandra, which appears to bring him much relief. I have left one well-contained patch as his personal dog bed…

img_0503Read about my efforts to eradicate a large patch of pachysandra that spread into a nearby moist woodland area on my property in The Year I Shall Win the Pachysandra War. Several years later, I can attest that I have finally won this war (I only pulled a few persistent bits of root this year), and I now see native plants making a comeback.

This is a reprint of an article originally published in January 2014 at the now defunct Native Plants & Wildlife Gardens.

Growing Native Perennials from Seed

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Unlike many native perennials, Purple Coneflower is quick and easy to grow from seed.

Must be easy to spread yourself around when you’re a plant that produces lots of seeds, right? After all, look at what happens when kids blow the seeds off dandelions! Dandelions pop up everywhere next year!

Unfortunately, it’s an ironic fact of gardening life that whatever you are trying to grow takes some effort, whereas the plants that you don’t want (aka “weeds”) just seem to appear without any help from you.

Now, even though regionally native plants (if sited correctly) tend to be easier than exotic plants to grow in temperate climates such as New England, that doesn’t mean that they will necessarily establish and spread without some help from us. You can buy established container plants from native plant nurseries, but this gets expensive, plus many commercially available natives are cultivars – genetically identical clones that contribute little genetic diversity and resilience to the species as a whole.

Here’s where we hands-on, DIY gardeners come in, by helping nature along a little bit!

The beautiful Butterfly Weed (Asclepias tuberosa) is very rare in the wild, but is easy to grow from seed from existing plants.

The beautiful Butterfly Weed (Asclepias tuberosa) is very rare in the wild, but is easy to grow from seed from existing plants.

In an ideal world, our plants would bloom at the right time, be pollinated by the right kind of insect or bird, form seeds and fruits that ripen and are carried (again, by bird, insect or wind) to an appropriate location to germinate when the weather is just right. Some of them do, and if they survive the first year or two, may become established plants that flower, go to seed and continue the cycle.

In the real world, though, seedlings don’t have a high survival rate. Seeds that are not picked right off the stem by hungry birds might, if they have the misfortune to blow into a lawn or roadside ditch, be mown down repeatedly or doused with weedkillers. Some seedlings are crowded right out by vigorous exotic (non-native) plants that make up about 40% of the natural vegetation in New England. Other seeds will just never germinate, no matter what. Such are the laws of life, genetics, and human-controlled landscapes.

Native plants such as Black Cohosh (Actaea racemosa) are often expensive to buy because they are slow to propagate from seed. Photo used by permission of Vincent Normand.

Native plants such as Black Cohosh (Actaea racemosa) are often expensive to buy because they are slow to propagate from seed. Photo used by permission of Vincent Normand.

So what’s a native plant gardener to do, if they want large quantities of native plants? Why, collect seeds and grow your own, of course! You can help support local plant and wildlife communities and have a beautiful, natural native plant garden by collecting seeds from existing natives and growing and distributing the seedlings around the landscape via friends, family and fellow citizens.

Collect seeds from plants that are as locally native as you can find — in Massachusetts this usually means buying mature flowering plants from nurseries at New England Wild Flower Society’s Garden in the Woods (Framingham and Whately) or our small nursery at Turkey Hill Brook Farm (Spencer). Try to find local plant suppliers that propagate from local seed banks. Avoid buying seeds from foreign suppliers or even other areas of the country–-seeds may not be adapted to grow in your particular climate. You can also collect seeds from native plants that you’ve seen growing and blooming locally – but never take more than about 10% of a plant’s seeds for your own use.

If you don’t have a cold frame, sow native seeds in recycled clear plastic containers with lids and place outdoors for the winter to protect them from critters or floods.

If you don’t have a cold frame, sow native seeds in recycled clear plastic containers with lids and place outdoors for the winter to protect them from critters or floods.

Best Way to Sow Natives?

The easiest way to grow from seed is by simply allowing plants to go to seed and letting nature do the seeding, but you may have little success with this if your gardens are heavily mulched or lots of critters are present to dine on the seeds. Because most native plant seeds need an extended period of time (sometimes several years) before they will germinate,  you’re usually better off sprouting native seeds in a protected area outdoors, such as a cold frame or greenhouse, and letting them take the time they need.

Learn Your Seed’s Needs

Do some homework to find out whether your seeds have any special requirements for germination. For example, our native milkweed and bee balm seeds require at least one winter outdoors in a moist environment before they will sprout. Wild cranesbill seeds are hydrophilic and should not be allowed to dry out in storage. Seeds from wild senna and goat’s rue require scarification/scraping of the seeds to loosen their hard seed coats to allow for germination. I use William Cullina’s book Growing and Propagating Wildflowers of the United States and Canada from New England Wild Flower Society, which lists germination requirements for each plant native to North America. Miriam Goldberger’s new book Taming Wildflowers also lists germination requirements for plants along with other tips for growing wild plants from seed. Prairie Moon Nursery has online germination requirements for the various native seeds that they sell.

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At Garden in the Woods, Trilliums and Squirrel Corn (Dicentra canadensis) are sown in raised nursery beds where seeds can sit through several winters and grow until plants reach their flowering stage. At that time, the best selections are transplanted to the garden or potted up for sale in the nursery.

Rudbeckia and Blue Lobelia (Lobelia siphilitica) are easy to grow from seed sown when they ripen on the plant.

Rudbeckia and Blue Lobelia (Lobelia siphilitica) are easy to grow from seed sown when they ripen on the plant.

Easy Native Perennials from Seed

For your first attempt, try growing the following eastern natives from seed — fresh or dried seeds usually germinate easily without any special treatment (cold exposure or scarification) in New England:

  • Aster
  • Lobelia
  • Helianthus
  • Rudbeckia

Native Seeds that Require At Least 1 Full Winter Before Germination:

Most of our northeast natives will only germinate after being exposed to several months of cold, snowy weather….in other words WINTER. As moisture-filled seeds freeze and thaw through winter and into spring, their outer seed coats break up, signaling seeds to germinate when temperatures get warm again. Locally-evolved plants are smart — their seeds know better than to germinate too early and have their babies get zapped by the cold.

  • Liatris seeds readily germinate in spring after a winter outdoors in moist soil.

    Liatris seeds readily germinate in spring after a winter outdoors in moist soil.

    Asclepias (also needs light to germinate, sow seeds on soil surface)Aquilegia

  • Echinacea
  • Eupatorium
  • Eutrochium
  • Geranium (hydrophilic seeds, do not let dry out)
  • Goldenrod
  • Liatris
  • Monarda
  • Phlox
  • Pycnanthemum
  • Tiarella
  • Verbena
  • Vernonia
  • Viola
  • Zizia

Some native plants only germinate after multiple winter/spring cycles of freezing/thawing:

  • Trillium
  • Actaea
  • Senna*
  • Polygonatum* (hydrophilic seeds, do not let dry out)

If you start early by sowing seeds in fall or early winter after collection, you might be able to coax seedlings from these the first spring after sowing.

img_1422-300x265Winter Sowing in Containers

On our farm, my free-range chickens love to pick at seeds and scratch up seedlings in my plant beds, so I collect seeds from my best plants in fall and germinate them in recycled plastic containers with lids, to protect them until they can germinate and grow a little bit.

Here is the native plant nursery that lives on our patio from early winter and spring each year — by late spring, I transplant seedlings into individual containers or directly into the garden:

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To sow seeds in plastic produce containers, poke holes in the bottom and top of the container, sow seeds on a few inches of moistened seedling mix, water well, and place the containers outdoors for the winter. When warm temperatures arrive in spring and seeds begin to germinate, open the lids on warm days. When seedling roots reach the bottom of the containers, you can transplant them, either right into the ground, or into containers to grow on until they are larger.

Winter sown seedlings grown in containers will be tiny in their first spring, but very hardy! Unlike seedlings grown indoors, they need no hardening off after lids have stayed open for several days and nights.

More Info on Native Plants and Winter Sowing:

WinterSown.org

Winter Sowing FAQs at GardenWeb 

How to Germinate Native Seeds from Prairie Moon Nursery

This article is reprinted from its original posting in May 2014 at the now-defunct Native Plants and Wildlife Gardens.