Growing Greener

by A. Goldman

Bounty from the garden

Improving our landscapes can create environmental benefits. Gardens can create habitats for wildlife, help clean the air, sequester carbon from the atmosphere, help manage storm water runoff, and even reduce our carbon footprint by growing food in our own backyard.  

Here are a few suggestions for making your garden even greener.

Follow the principals of integrated pest management (IPM). Use the least invasive and toxic method possible to control pests and diseases.

Compost bin in vegetable garden

Yard waste comprises up to 20% of a landfill. Most of these materials are biodegradable and can contribute to soil health.   There is a technique to composting kitchen and yard waste if you want results quickly, but it does not need to be complicated. A simple heap of materials will eventually break down, no turning or management needed if you are patient.  No room for a compost pile? Consider “in place” or “trench” composting right in the soil.

You can also use yard waste to mulch in place. When trimming back your garden this fall use the chop and drop method. Chop up large leaves and stems and let fallen leaves remain around the plants.  Using green materials in place can prevent erosion, increase your soil’s viability and smother weeds. However, do not chop and drop if the plants are diseased – diseased materials should be removed.

Create a Habitat Pile for birds, toads, and small critters with excess of twigs and branches.  If you don’t have the room for that, just breaking up smaller twigs and adding to the garden makes a difference. These will break down quickly and the smaller they are, the less you will see them.  Larger pieces can be used for plant stakes, defining path edges, helping to hold soil back on a hill or even pot feet under your planters. 

Gardeners usually generate a significant number of empty nursery pots every season.  The best solution is reuse, especially since nursery pots are not usually recycled even if they are included in your recycling bin. If you know of a fellow gardener who shares or propagates plants from their garden, ask them if they could use quart or gallon pots. Pots can also be used in large planters at the bottom to make it lighter and reduce the amount of potting soil needed.   They are great for pot-in-pot planting. You bury a black plastic pot to ground level and then it can accept another already potted plant.  This allows you to change out what is planted in that particular spot at any time.  Planting spring bulbs this way allows you to protect bulbs from voles and if you put some hardware cloth over the top, from squirrels. Once the bulbs are done blooming, you can then opt for something else in that same spot. 

If possible, buy mulch and soils in bulk to avoid all the plastic bags. Consider re-using the bags you do get as trash bags in your shed or garage in place of a new trash bag.  Cleaned bags can be kept in your car when plant shopping.  Place your large plants or groups of smaller in a rolled down bag to keep them upright and contain any soil from the bottom of the pot.  

Plant Profile – Zizia aurea

Zizia in the garden

Zizia aurea has the common name Golden Alexanders. It is an easy to grow native plant that no native plant garden should be without. It has lovely umbels of bright yellow flowers that bloom for a long time in spring to early summer – when many of our native plants are just starting to think about flowering.

The flowers are important to a number of short-tongued native bees and other insects that are able to easily reach the nectar in the small yellow flowers.

Swallowtail caterpillar hiding in the Zizia

Zizia aurea is also a host plant for Black Swallowtail butterfly caterpillars.

Zizia can grow in considerable shade but will flower better in full sun to light shade.  Plants look best in a grouping. They can grow to 3 feet with the flowers, but flower stalks can be trimmed back after flowering to control height. While perennial, Zizia can be short lived so allow some reseeding to make sure it stays in your garden.

Want to know more? Here are a few links.

Missouri Botanical Garden – Zizia aurea

Lady Bird Johnson Wildflower Center – Zizia aurea

Tasks for the September Garden

Agastache ‘Golden Jubilee”

September is for planting! The soil is still warm but the air is cooler and moisture is (usually) more abundant. These conditions are great for establishing most herbaceous perennials, trees and shrubs. Planting them now will give you a head start on spring. The exception to this is broad-leaf evergreens like rhododendrons, boxwood and hollies as well as plants that are borderline cold hardy (for us, zone 7 or higher). These are better planted in spring.

Zinnia

Give your ornamental planters a boost. Remove or trim back any ragged annuals. You can replace them with hardier fall plants.

Now is a good time to save some seeds for planting next year. Seeds from many annuals like Zinnia, Marigold, Cosmos, and Celosia are easy to save in a cool dry place. Just be aware that some hybrid varieties will not be identical when grown from seed.

Japanese Stiltgrass

Speaking of seeds – get after those weeds! Many weeds like Japanese stilt grass, yellow oxalis, pokeweed and various grasses are setting seeds. Getting rid of them now will help reduce populations next year. Also remove the flower heads of self-seeding annuals and perennials if you don’t want the seedlings.

There is still time to add cold hardy vegetable starts (lettuce, kale, broccoli, etc.) to the vegetable garden. If you are quick you can still seed in lettuce, radishes, kale and spinach.

Early Peony

While Peonies can live a very long time without dividing, now is the best time to divide them if you want to increase your plants.

Now is a good time to do soil tests. If pH needs to be adjusted, this is best done in fall to prepare for spring planting.

It’s also a good time to start a new planting bed by laying down cardboard and then layering woodchips, twigs, stems and fall leaves when they fall. By spring, the area should be ready for planting.

Think about bringing in any houseplants vacationing outside. They should come in before nights hit 50F. Inspect for pests (especially mice living in large pots – ask me how I know…). 

You can also bring in some herbs and place them in a cool, sunny spot in pots with good drainage.

Make a list of potential new plants to add to your landscape and have the list handy when fall plant shopping.  If you don’t have a specific plant in mind, make a list of the spaces you want to fill – including the amount of space, the light and moisture conditions and any height constraints. You can use this to help choose plants when shopping.

Keep swatting those lanternflies…

Plant Profile: Baptisia

A perennial with presence

Baptisia australis flowers

Baptisia is a tough, deer and rabbit resistant group of herbaceous perennial plants that provide beautiful spires of flowers in spring and handsome, disease and pest resistant foliage the rest of the season.

Baptisia is commonly known as false indigo or wild indigo because a blue dye can be made from some species. Dye made from Baptisia was exported from the colonies to England in the 1700’s.

Baptisia australis

Baptisia australis, a blue flowering species, is native to Pennsylvania. Other Baptisia species have flowers in white (Baptisia alba) and yellow (Baptisia sphaerocarpa). These different species have been crossed to create many beautiful and robust garden perennials.

Baptisia flower best in full sun and pretty much any average garden soil – they are not pH sensitive. Because of their extensive tap root they shrug off drought, but this also makes them difficult to move once established. They create sizable, shrub-like plants when they mature so be sure to take note of the chosen cultivar’s size and leave room for growth. The seed pods can be attractive in winter, but if desired plants can be trimmed after flowering to control size and prevent any flopping on to neighbors. Baptisia will push out new leaves after trimming to cover any rough cut stems.

Baptisia ‘Decadence® Lemon Meringue’

It’s generally better to plant Baptisia in the fall in our warmer climate, but it can be planted anytime. Just be sure to give it some water its first summer if you plant in spring.

Because Baptisia grow to shrub size every year, they appreciate a top dressing of compost or a dose of slow release fertilizer. Be careful working around the plants in spring because breaking off the new growth will eliminate flower buds.

Baptisia can be slow to get started in the garden because it’s busy underground building its root system, but be patient and you will be rewarded with a beautiful, dependable, long-lived plant. Bet on Baptisia – you won’t be sorry.

Want more information? Here are some links:

Mt. Cuba Botanical Garden Baptisia Trials report

Missouri Botanical Garden Plant Finder – Baptisia australis

Clemson Cooperative Extension – Baptisia

Mini and Dwarf Shrubs

Smaller is sometimes better

Article by A. Goldman

Hydrangea quercifolia ‘Ruby Slippers‘ in summer

There are many reasons to think about adding small shrubs to your landscape.  As many gardeners downsize or have mature plantings at their properties, it is wonderful to see new versions of old favorites being introduced.  Not everyone can devote enough real estate for a VW bug-sized shrub that may only bloom once a year but now you can get one that is only a fraction of its previous size. 

Replacing plantings of annuals with small shrubs can reduce maintenance and expense over time. Smaller shrubs can be tucked around existing trees and large shrubs to reduce the need to mulch. Small shrubs can even be planted in large containers to simplify annual planting and provide year round structure.

Here are a few suggestions for small shrubs. They are divided into mini shrubs which mature under two feet and dwarf shrubs  which are considerably smaller than the original but may still reach four feet or so.

Mini shrubs to consider:

  • Tiny Tuff Stuff Hydrangea: 18-24” re-blooming lace cap hydrangea
  • Lil Ditty Viburnum: 24” fragrant white flowers and fall color part shade tolerant
  • Yuki Cherry Blossom Deutzia: 1-2’ pink flowers, use as a groundcover
  • Double Play Gold Spirea: 24” golden foliage with hot pink flowers, deer resistant
  • Ground Hog Aronia: 14” native, white flowers and purple berries, tough plant
  • Carsten’s Wintergold Mugo Pine: 1-2’ winter golden needles, hardy to Z2, rugged
  • Petite Knock Out Rose:  18” same vigorous growth and continuous blooming

Dwarf shrubs to add:

  • Sugartina Clethra:36”  Native, easy care, bee attractor, fragrant flowers
  • Red Rover Dogwood: 5’ Native, great fall color, red stems, pollinator and bird beneficial
  • Little Quickfire/Little Lime Hydrangea:  5-6’ tried and true, die hard hydrangeas
  • Ruby Slippers Oak Leaf Hydrangea: 3-4’ with a large flower inflorescence and nice fall color
  • Scent and Sensibility Lilac: 3’ wider than tall, fragrant, purple and re-blooming
  • Crimson Kisses Weigela: 3’ re-blooming red flowers with white, easy care
  • Winecraft Gold Smokebush:  6’ golden foliage, smaller and denser than regular smokebush

Take a look around your landscape to consider where you might tuck in some added interest with these smaller shrubs.  They are a great transition from larger shrub and trees and make a nice backdrop to perennials.  Consider adding a few to offer more cover for the birds and critters that call your garden home.  Smaller is better!

Hydrangea quercifolia ‘Ruby Slippers‘ in fall

Beyond Milkweed

Bringing in the Butterflies

Many know the importance of supplying milkweed as a food source for Monarch butterfly caterpillars, but there are other plants you can add to your yard to support other butterfly species.

Zizia aurea in bloom

Eastern Black Swallowtail caterpillars will feast on Zizia aurea. This native perennial has cheerful unbrels of yellow flowers in spring and will grow in full sun or part shade. Eastern Black Swallowtail will also eat dill, parsley, fennel and carrots – if you are willing to share.

The Pearl Crescent relies on our native asters like Symphyotrichum cordifolium (blue wood aster), Symphyotrichum oblongifolium  (aromatic aster), Symphyotrichum laeve (smooth aster), or Symphyotrichum novae-angliae (new england aster). Asters are beautiful flowering plants that also provide late season nectar for butterflies and bees. There are many lovely cultivars to choose from – one to fit almost any garden space.

Antennaria plantaginifolia in bloom

Antennaria plantaginifolia is a food source for the American Painted Lady butterfly . The caterpillars roll the plant’s leaves to make sheltered cocoons. This plant makes an attractive low growing ground cover in sunny, dry well drained places.

Woody plants contribute to butterfly survival too. The Spicebush Swallowtail depends on our native spicebush (Lindera benzoin) and native Sassafras tree (Sassafras albidum). Wild cherry (Prunus serotina) supports Spring and Summer Azure caterpillars and Eastern Tiger Swallowtails. If you grow our native Pawpaw trees (Asimina triloba) not only could you get tasty fruit, you might be lucky enough to see a Zebra Swallowtail.

Great Spangled Fritillary

Having a less than perfect lawn is also a big benefit to butterflies. The Great Spangled Fritillary relies on common violets. Leaving violets in your lawn (or having a patch as a groundcover) is vital to these beautiful butterflies. White clover supports a host of butterflies including the Orange Sulphur, the Gray Hairstreak, the Eastern Tailed Blue and the Clouded Sulphur. It is also a terrific source of nectar and pollen for bees and improves soil by sequestering nitrogen.  

Since some butterflies and moths winter over as caterpillars or chrysalises (and sometimes even as adults) in leaf litter and plant debris, try to wait till the weather warms in spring before doing too much clean up. Wherever possible, leave fallen leaves in place. This will protect hibernating butterflies (as well as other critters) and will provide you with free, nutritious garden mulch – its a win-win.

Eastern Tiger Swallowtail on Tithonia rotundifolia

No Longer Impatient for Impatiens

By A Glodman

Welcome back old friend!  The ubiquitous annual that all shade gardeners loved is back and ready to create season-long color.  Impatiens are what we are discussing. 

Beacon Impatiens – photo courtesy of Ball Seed

Impatiens walleriana were attacked by Impatiens Downy Mildew (IDM). This disease caused defoliation and eventual death of impatiens well before the growing season ended. The disease was difficult to control; and airborne and overwintering soil spores re-infected new plants. This disease essentially ended sales of the once common annual.

Other annuals came to the shade gardener’s rescue; Begonia, Torenia, Coleus, New Guinea impatiens, and Caladiums but some things can never be duplicated. 

Through a collaboration of plant breeders and extensive plant trials in Washington State, Michigan, Colorado, Texas, Minnesota, England, Australia, South Africa and here in Pennsylvania at Penn State, two varieties were deemed to be worthy and will be introduced for sale in 2020. 

Beacon and Imara are the two brand names these new impatiens will be sold under.  The Penn State trials that were overseen by Sinclair Adam revealed Beacon to be slightly better in Pennsylvania gardens.  Both Beacon and Imara are hardy and vigorous for your garden but with any plant, conditions may favor one variety over the other.  Color variety is not as extensive as previously but I am sure with time we will have many more to choose from.

Keep an eye out this spring for the reintroduction of this hardworking, floriferous, easy care annual. 

Meet Sweet Box

By C StClair

Are you familiar with the plant commonly known as “Himalayan Sweet Box” (Sarcococca hookeriana var. humilis)?  This is one of those plants I dearly love, especially this time of the year.

Sweet Box is actually a shrub, but it is very low growing and spreads, creating a ground cover. No worries about a horticultural invasion.  It spreads slowly – you’ll actually wish it spread faster than it does.

It does need some shade – especially during hot afternoons.  If it gets too much sun in winter, the leaf tips might brown a bit.  But once it is established, it can tolerate dry, shady soils – even those under established trees. It looks fresh, green and tidy all season.

The common name “Sweet Box” is very fitting. It maintains it shiny green leaves like a boxwood (although they are larger and pointy), but it gets small, intensely fragrant flowers in very early spring (in my garden – about the same time as the snow crocus). Brought inside, the flowers can subtly perfume the entire room.

One caution though, Sarcococca hookeriana is susceptible to boxwood blight so if you know you have boxwood blight on your property this may not be the best plant choice.

Pennsylvania Gold Medal Plants for 2020

By C StClair

Every year the Pennsylvania Horticultural Society recommends a selection of plants that they feel will be outstanding performers in the mid-Atlantic home landscape.

The selections are made by a committee of growers, nursery owners, landscape designers and other horticulturalists who have had the opportunity to observe the plants over time. They are chosen for their hardiness, pest and disease resistance, ease of growing and maintenance – as well as appearance of course.

This year, they have singled out one tree, 2 shrubs and 3 herbaceous perennials.

The tree is Carpinus caroliniana, commonly known as American Hornbeam but sometimes called Ironwood or Musclewood. It is an understory tree so its smaller size can be useful in home landscapes. It is slow growing to about  20-30 feet and has orange- yellow fall foliage. This tree is native to the mid-Atlantic.

One of the chosen shrubs is Aronia melanocarpa ‘Viking’, also known as Black Chokeberry. This native shrub has fragrant white flowers in spring that turn into glossy black berries in late summer. The berries are edible (although astringent) and can be cooked into pies and jam – or left as a food source for birds. The glossy leaves have good red fall color. ‘Viking’ is a cultivar selected for greater fruit production. This shrub grows 3-6 feet tall and wide. It can tolerate part shade, but flowering and fruiting are best in full sun.

Image courtesy of Northcreek Nursery

The second shrub is Hydrangea arborescens ‘Haas’ Halo’, a cultivar of our native Smooth Hydrangea. This shrub has large lacecap flowers with sturdy stems that don’t droop after a rain. The lacecaps can be as much as 14 inches in diameter and are sturdy enough to provide winter interest. The flower heads include both showy, sterile flowerets and fertile flowers so they provide more pollen and nectar for insects than the more common ‘Annabelle’ hydrangea. Haas’ Halo also appears to be more drought tolerant (once established) than ‘Annabelle’.  This shrub grows 3-5 feet tall and wide in part to full sun.

Coreopsis verticillata ‘Zagreb’ is a compact herbaceous perennial with a light, airy texture. The bright yellow flowers cover the plant from early through mid-summer, with a re-bloom in fall if the plant is cut back to half after flowering slows. ‘Zagreb’ is useful for the front of a border or in pots. It can tolerate poor soils and drought. It does need good soil drainage to prevent crown rot. This perennial is compact (12-18 inches tall and wide), long flowering and long lived.

The second perennial selected is Geranium X cantabrigiense ‘Biokovo’, commonly known as Cranesbill Geranium due to the shape of the seed pods. This plant is low growing and compact, about 6-12 inches tall. It flowers in spring with white flowers tinged slightly with pink. Although somewhat slow growing, it can create a groundcover over time.  It grows best in full sun to part shade. While it can tolerate some drought, it may go dormant in late summer in dry conditions. It performs and spreads better in consistently moist, well drained soils.

Although technically a woody sub-shrub, the last selection chosen is usually grown as an herbaceous perennial. Perovskia atriplicifolia ‘Little Spire’  (commonly known as Russian Sage) is a compact selection growing to about 2 feet tall versus 4 feet tall for the species. ‘Little Spire’ grows best in full sun and medium to dry soil moisture. It is drought tolerant, deer resistant and has attractive silvery foliage. The spires of blue to violet flowers bloom for a long period over the summer.

February Fun in the Garden

By A Goldman and C StClair

With days getting a bit longer, the urge to get outside and “do something” starts to grow. Here are a few tasks to consider tackling this month. But keep in mind, soggy, wet soils compact very easily. Avoid walking or driving on wet soil whenever possible.

Keep outdoor evergreens well-watered and even deciduous plants if they were planted late in the season.  Dry roots and drying winds will challenge evergreens to stay hydrated. Check for any deer browsing and net or apply repellent if evergreens are being chewed.

Keep an eye open for perennials that have heaved out of the soil due to freeze thaw cycles and gently push them back in place to prevent roots from drying out.

If you have bird baths, try to keep fresh and unfrozen water in them for not only birds but other animals that need a drink. 

On mild days, go outside and clean out your birdhouses for future residents.

Its hard to resist the desire to start garden clean up on those mild days that pop up here or there, but try not to disturb the gardens too much yet (except for maybe pulling out some of the evil Hairy Bittercress). There are valuable critters sleeping in the debris and they need days consistently above 50 F to wake up for the season.

Use downed branches to start or add to a brush pile for the critters that share your property.  These are great in far corners away from view and help with habitat.  For information on brush piles click here.

If the weather is nasty, there are indoor tasks to do as well.

Dust your indoor house plants.  They can photosynthesize much better without a layer of dust on their leaf surface. Be careful not to over water or fertilize.  They are not as energetic in the winter, quite like us!

Take some time to peruse catalogs and on-line plant sources. Dreaming about amazing new additions to the garden is half the fun. Before you place those orders, stop to consider and reassess where those plants will go in your landscape and if you will have time to plant/care for them.  Unusual items are worth the order but more “common” plants might be purchased at your local nursery in a larger size for the same cost.

Now is a good time to organize your records and get your plant tags ready for spring.  If you have records of plant purchases for the previous year, use that for making tags to place when weather is mild or when spring finally arrives.