Here's what three things I'm obsessed with this fall

ONE:  Rain gardens, vegetated swales, dry stream bed gardens - by whatever name (one potential client referred to it as a "glorified ditch") these stormwater management facilities are challenging and fun to design and implement.  Especially in small spaces.  My goal is to include stormwater management facilities in every design.

TWO:  Water gardens - not as difficult as I thought they would be.  It's been awe-inspiring to watch a 'Black Magic' colocasia grow from three small leaves into giant, beautiful gorgeousness, with runners spreading all over the place!

THREE:  The challenge of improving the streetscape on Main Street - what are low-cost, creative ways to invest in making our Main Street business district more "beautiful" when there is no money available?  And how do you convince "the people" that it's important enough to pay attention to?  I installed two "mini-gardens' this fall in empty tree wells along Main Street to demonstrate that treating the tree well essentially like a container (perennials, a shrub or ornamental grass, some annuals and bulbs) can look (almost) as nice as a street tree (and certainly nicer than a mostly-dead tree or gravel!).

Some of Mike Ruggerio's Favorite Perennials

Mike Ruggerio, one of my favorite teachers from NYBG, basically knows everything about anything related to trees, shrubs, perennials, annuals and bulbs.  His talks are always both funny and fascinating – you never fail to learn about a million new things.  And you long to see what his own gardens are like!

This particular talk was on new perennials – new cultivars that fit his definition of a perennial – “a plant that comes back after more than two years”  - meaning they are cold-hardy, adaptable, easy, beautiful and for the most part long-blooming – many also deer resistant.

I’ve chosen a few that I love too, or that I’m definitely going to try.

• Achillea ‘Oertel’s Rose’ (yarrow) is a lavender-pink, gentle form of yarrow – a nice alternative to golden yellow that fits in well with the purple/white/pink/chartreuse/burgundy garden.  I love the fresh foliage of yarrow in the spring – it’s one of the earliest.  BUT it’s a dry meadow plant – it won’t be nice if you don’t have the right conditions.

• Actaea ‘Hillside Black Beauty’ and ‘Black Negligee’ (bugbane) are dark-foliaged cultivars of the green-leaved species.  Bugbane is wonderful in shade, with mounds of almost-black foliage and fragrant white wand-like flowers rising up several feet above the foliage in autumn.  It’s an excellent back-of-the-border choice for your shade garden.  The newest cultivar ‘Black Negligee’ has foliage that is more purple than black – we’ll see if we can get better photos this season that show it’s purple-ness.  ‘Black Negligee’ typically grows to 4-5’ tall and is a noteworthy addition to the garden for its deeply-cut, dark purplish-black leaves on branched, dark stems.  The foliage has a lacy effect, hence the cultivar name, and makes an effective accent throughout the growing season.

Black Negligee

• Corydalis lutea (yellow corydalis) seems to have it all if you’re in the market for a self-seeding spreading deer-resistant ground cover for shade that flowers from May till frost.  It’s easily grown in average, medium, well-drained soil in part shade to full shade. Corydalis doesn’t tolerate wet feet, and wet soils in winter can be fatal.   It forms a mound of ferny, medium green foliage to 15" tall and 18" wide and produces bright yellow flowers.   It’s great for shaded rock gardens or border fronts and forms a nice ground cover in shady woodland areas.  Wear gloves – the sap is very irritating.

• Echinacea purpurea ‘Fragrant Angel’ (coneflower) has taken over as “best white coneflower”.  It’s a pure white color that stays white and it’s also quite fragrant.  Don’t plant it if you have groundhogs – they’ll come from far and wide and eat every bite on the first day.

• Hemerocallis X ‘Barbara Mitchell’ is his favorite daylily – a “true pink” flower 6” wide.  He also enthused about H. X ‘Bill Norris’, a golden daylily that grows 4 ft tall.

Hybrid daylily 'Barbara Mitchell'

Hybrid Daylily 'Bill Norris'

• For those of you who don’t already know about Geranium macrorrhizum (bigroot geranium), here’s another shade plant/groundcover that is deer-resistant, has either white or pink flowers, spreads enthusiastically by runners, has a nice fall foliage color and is semi-evergreen in our area.  It flowers in May – June, and after that is just a mound of foliage.

• Another geranium that he mentioned in passing is one of my new favorites – Geranium X ‘Midnight Reiter’ (cranesbill) – it has purplish-black leaves and dusky blue-violet flowers.  It goes with everything, and, like most cranesbill, spreads nicely.

• His favorite new aster cultivar, Aster tataricus ‘Jin-Dai’ (tatarian aster), a full-sun standout that blooms in October when basically nothing else is flowering.  ‘Jin-Dai’ is a compact cultivar (believe it or not!), typically growing 3-4' tall.  (The species may reach 6-7' tall).  Distinctive almost tobacco-like basal leaves are up to 18" long and 5" wide – interesting foliage for the spring garden. Dense and abundant blue flowers with yellow centers appear in autumn on rigid stems. This late bloomer doesn’t need pinching to control height and doesn’t flop (i.e. doesn’t need staking) as long as it’s in full sun and usually blooms until the first frost.  Added bonus - attractive to butterflies!

The Gardens at Wave Hill

Five Principles of Landscape Design That You Can See at Wave Hill and Use in Your Own Garden

 Sometimes the process of fine-tuning your garden or landscape can seem a daunting task.  One way to make it easier is to use public garden spaces as a resource for seeing landscape design principles put into practice.  Wave Hill in Riverdale is a public garden and cultural center which is nearby, fun, beautiful, and a source of inspiration in every season.  Originally an estate, the property was donated to the City of New York in 1960, and over several decades the gardens were restored and reinvented by the internationally acclaimed horticulturalist Marco Polo Stufano.  Wave Hill “is renowned for its intimacy of scale and its carefully cultivated serendipity: at Wave Hill, even the most seasoned gardeners can take joy in the unexpected.”  Wave Hill is one of my favorite gardens, and I’d like to share with you some of the lessons it has taught me.

Design Principle 1:  A garden should have “good bones”.  The “bones” of a garden include pathways, structures (arbors, trellises, pergolas, gazebos), statues, containers, walls, fences, ponds, fountains and all the different materials they are made from, as well as the trees and shrubs.  “Bones” also include the geometry of the space; how the elements relate to each other.  Get a map of Wave Hill from the Visitors Center.  It’s a simple, almost stylized map.  To evaluate the “bones” of your own garden, start by making a similar map of your landscape.  Look at how the walkways are situated.  Are they curved?  Do they lead to any surprises?  Where are the planting beds relative to the walkways?  Are you invited in?  At Wave Hill, you enter from the far end of the parking lot on a narrow path.  Directly in front of you in the far distance are the Palisades.  In the middle distance is a pergola.  Notice that the path does not lead directly to the pergola.  Instead, it curves to allow you to slow down and begin to meander through the garden.  

The pergola at Wave Hill in winter, with the silhouette of a hornbeam beyond and the Palisades in the far distance.

 As you walk through the garden looking at bones, notice how the perennial garden is situated to the side, surrounded by a rustic fence that sets the tone for what’s inside.  You need to walk through it to see what’s in it.  Each bed is a mini-garden in itself, and a lesson in how you can set up your own small perennial garden without being intimidated.  Each bed has its own “bones” – notice how large shrubs, small trees and even garden ornaments provide structure to each bed.  This can be best appreciated in winter – find a day to visit when the paths aren’t covered with snow, and notice the strong axial structure of the perennial garden.  

Continue through the perennial garden and emerge on a small side path that leads you toward the herb garden.  The designer has made use of the old stonewalls and the foundations of the old greenhouses, to plant in and among them.  This is much more interesting than if those elements had been removed.  The walls provide a backdrop for the plants; a contained and defined area that is clearly designated.  Also notice how the planting beds for the herbs have been defined – each bed is essentially the size of one of the bluestones used for the path, creating a strong symmetry, and beds are divided from one another using bluestone set on edge.  The herb garden is constructed on the footprints of old greenhouses, with the old walls as a backdrop and bluestone paths giving access to all the planting beds.

Design Principle 2:  Strive for four-season interest.  Yes, you can have flowers in winter!  At Wave Hill if you visit in February and March, you'll see winter jasmine (Jasminum nudiflorum), witch hazel (Hamamelis X intermedia), and cornelian cherry dogwood (Cornus mas) in bloom in late winter.  Additional elements with winter interest include red and yellow twig dogwood, pussy willows, black pussy willows, architectural trees (like magnolias, beech, hornbeam), seed heads, exfoliating bark, and berries.

Lagerstromia (Crapemyrtle) bark is fabulous anytime, but especially glowing in the winter sun.

Design Principle 3:  Plant a tree!  At Wave Hill you will find lots of “specimen” trees, both large and small.  A “specimen” tree means that the tree has been planted by itself or in a small grouping so that its attributes can be appreciated.  You'll see Lagerstromia (Crape myrtle), Parrotia, Magnolias, Paperbark Maple, English Oak, Dawn Redwood, Elm, Copper Beech, Weeping Beech and Hornbeam.  You can have any of these trees in your landscape as well, provided you have the appropriate conditions of wet-dry-sun-shade for the tree you’ve fallen in love with.  Notice how the trees at Wave Hill are placed relative to the paths and the beds in places that “make sense” visually – they are connected to their surroundings.  Notice that many of them are simply planted with a mulch circle around the base.  This is an excellent way to include a specimen tree in your own landscape, without feeling that the tree needs to be under-planted or included with other shrubs in an elaborate island.

Design Principle 4:  Add annuals effortlessly to your landscape by using containers.  The strategy used by the designers at Wave Hill to add annuals to the garden is to plant a single type of annual in a container and then group containers together.  Containers with different shapes and sizes are selected, then arranged to form a tapestry of color, height and texture.  When one type of annual gets past its prime, the container is simply removed from the design and a new one is introduced.  Using this trick, you can keep your annual displays looking fresh all through the season.

Design Principle 5:  Take time for tea.  At Wave Hill, outdoor chairs are moveable, plentiful and weatherproof.  You can bring a chair under a tree, out into the sun or under the pergola.  You can sit by yourself or in a group.  Talking, reading, or just sitting is the order of the day.  You can sit on the terrace by the Café and be amazed by the majestic view of the Palisades.  Sip tea.  Munch on a cookie.  Have lunch.  Invite a friend.  Recharge your batteries.  Revel in the changes of the seasons.  Take this principle to heart for your own garden.  Sit in it.  Enjoy it.  Take a break.  Feel the quiet even as you hear all the noises of birds and kids and distant (or maybe not so distant) leaf blowers.  

Wave Hill is located 675 West 252nd St., Bronx NY.  Call 718-549-3200 or visit www.wavehill.org for more information.

Colored Stems and Leaves

Have you ever wondered why some trees and shrubs have colored stems and leaves?  

Colored leaves are important for landscape design, since the interplay of colors and textures adds beauty and interest.  

Forest Pansy Redbud leaves

Ninebark 'Diabolo'

Colored stems, like those of red twig or yellow twig dogwood, are an excellent way to add winter interest to a landscape.

So here's what I've found out Leaves and stems contain pigments – molecules that absorb specific wavelengths of light.  Chlorophyll gives leaves their green color because it absorbs all wavelengths except green.  Carotenoids produce yellow and orange colors – plants that are orange or yellow (corn, carrots, daffodils, bananas) are rich in these pigments.  Anthocyanins absorb blue, blue-green, and green light, so that reflected light appears red.  Anthocyanins give color to cranberries, red apples, concord grapes, blueberries and tree and shrub varieties with purple leaves.  Unlike chlorophyll and carotene, anthocyanins are not attached to cell membranes, but are dissolved in the cell sap. Because anthocyanins are in sap, stems and twigs can be red as well.

During summer, high levels of chlorophyll production cause leaves to appear green, largely by masking other pigments.  Water and nutrients flow from the roots, through the branches, and into the leaves.  The sugars produced by photosynthesis flow from the leaves to other parts of the tree, where some of the chemical energy is used for growth and some is stored.  The shortening days and cool nights of fall triggers a cascade of changes in trees, including decreased chlorophyll production (so that other pigments are unmasked and the leaves turn from green to yellow, orange or red) and increased amount of sugar in the sap (because the tree is not growing anymore).  In some trees, as the concentration of sugar in the sap increases, the sugar reacts to form anthocyanins. These pigments cause leaves, twigs and stems to turn red.  (Also an indicator of when anthocyanin-containing fruit is ripe – high sugar content in the cells). 

The range and intensity of fall color is greatly influenced by the weather.  Low temperatures destroy chlorophyll, and, if they stay above freezing, promote the formation of anthocyanins.  Bright sunshine also destroys chlorophyll and enhances anthocyanin production.  Dry weather, by increasing sugar concentration in sap, also increases the amount of anthocyanin.  So the brightest fall colors are produced when dry, sunny days are followed by cool, dry nights.

Some botanists also think that anthocyanin production is protective – by producing this pigment the plant is protecting itself from potential damage from UV rays that can be very intense in the winter.

As the tree starts to grow again in spring, the stored nutrients start to be used up, the sap starts to flow and the tree starts to produce leaves.  The anthocyanins break down so that the bright color of the stems fades. 

Because the genetic make-up of the individual tree or shrub determines the balance of pigments and the factors that influence their production, different cultivars can be selected based on the intensity of the red/purple color of their leaves and stems and its sensitivity to length of days and weather conditions.  That’s undoubtedly why some purple-leaved cultivars look mainly green at the height of summer and others look purple all the time, as well as why the purple color is less intense in some cultivars if they’re not getting enough sun – not enough sugar in the sap to support anthocyanin production in that particular cultivar.  Also why new cultivars of red twig dogwood can be selected for brighter red stems.

Deer resistant evergreens

I've designed and installed plantings all over Westchester County: the shores of the Long Island Sound, the hillsides along the Hudson, homes next to golf courses, lakes and wooded areas, and rural areas in the northern part of the county.  Many of these plantings were done without benefit of deer fencing in deer-infested areas.  There are a handful of trees and shrubs that are my go-to  plants in these situations. These are the ones you should try if you have deer wandering through your property unchecked and have had problems with deer browse damage on your existing plants.  The caveat is, of course, that if the deer get hungry enough they may eat plants that they've never eaten before.  So no guarantees!  But try them anyway!

Evergreens that are deer-resistant are the most important category, since they  are integral to the "bone structure" of your garden, and are important for privacy screening as well.  The most reliably deer-resistant evergreen is boxwood.  Deer really leave it alone!

Other broadleaf evergreens that I often use are skimmia (Skimmia japonica), andromeda (Pieris japonica) and sweetbox (Sarcococca hookeriana).  If I want to add some flower power and have the right conditions, I plant hybrid mountain laurel (Kalmia hybrids).  New Kalmia cultivars are entering the Nursery trade every year, with more spectacular bloom colors and compact, neater silhouettes.

Another excellent choice is American holly (Ilex opaca).  It takes shade, and is actually found in the forest, but it doesn't mind some sun either.  It is a tree, though, so give it enough space.

The needle evergreens (conifers) that I turn to are Norway spruce (Picea abies), Oriental spruce cultivars (Picea orientalis), Colorado Blue spruce and its cultivars (Picea pungens),  limber pine (Pinus flexilis) and concolor fir (Abies concolor 'Candicans'). 

A few favorite deer resistant ornamental trees and shrubs

Ornamental small deciduous trees and shrubs lose their leaves in winter, so they're only at risk of being devoured during the growing season. There are quite a few choices in this category, but I have a few favorites that are reliably left alone, and that have other qualities that make them interesting and valuable additions to the landscape.

Flowering quince (Chaenomeles speciosa) is a thorny shrub which flowers in very early spring and you can cut branches in late winter to force indoors.  Amelanchier or Shad (Amelanchier hybrids) is a multi-stemmed small tree with delicate white flowers in early spring, juicy berries beloved by birds in summer, beautiful fall color and showy bark in winter.

Of course, nothing can beat American dogwood (Cornus florida) for beauty in the spring, and new cultivars are becoming available that are much more disease resistant than the species.

I also love I also love the less commonly planted enkianthus (Enkianthus campanulatus), fothergilla (Fothergilla gardenii) and Virginia sweetspire (Itea virginica) - all have spring flowers and spectacular fall color.  And viburnums are versatile yet beautiful, so I use them often.  Both doublefile viburnum (Viburnum plicatum v. tomentosum) and fragrant viburnum (e.g. Viburnum carlessii and other cultivars) have beautiful flowers, a dense habit, berries and good fall color.  ■

Enkianthus blossoms

Enkianthus Fall color