Designing with Winter Interest Plants

In many areas of the country winter captures nearly four to six months of the year so designing with winter interest plants is a hugely important aspect of our designs. While the summer garden can be intricate and detailed, the winter landscape tends to need a bolder and more gestural consideration. We always ask the question….. will this garden also be compelling even in the winter months? We strive to consider all the aspects of garden design (form, flow, accent, figure/ ground, etc.) from a seasonal interest perspective. We look to accomplish four important goals in our winter landscapes.

DESIGN GOALS

  • Four-season interest in our plant selection. Structures and physical elements consider snowpack conditions and subtle winter colors. Outdoor spaces still seem warm and inviting. Materials can withstand harsh winter environments.
  • The beautiful, subtle and evocative landscapes that exists around us every day inspire our cultivated landscapes. A dark black perennial stream that cuts sharply through the stark white snow, the bright yellow and red of the willows and dogwoods in the spring when the sap flows but the snows still fall, soft rolling landforms covered in smooth buttery snow or the dark and light contrast of an evergreen against a snowy or subdued backdrop…. these are the inspiration behind our gardens.
  • Choosing winter interest plants for the garden is very similar in principle to our summer gardens, for example, uncut native grasses can provide soft texture and great movement even covered in snow. Large swaths of red twig dogwoods and the striking bark of a quaking aspen or birch grove can be a bold statement that is even more dramatic in the winter. Evergreens are easy choices to still have great structure in the garden, creating and maintaining spaces even in winter. Sizing winter interest plants to your average snow conditions so they will still stand out is an important consideration.
  • As winter conditions in many parts of the country vary greatly each year, desgning with winter interest plants can be even trickier. Winter resiliency (72 degrees in NY, NY on Christmas 2015, or 19 degrees in 2013) is important and plants that entertain all sorts of conditions are important.
  • Fire and water features, structures or sculptures often provide a focal point in our gardens because they can function well in both summer and winter. Place these features where the microclimate will be comfortable year-round…. Wind protected and south facing.

GARDENER RECOMMENDATIONS

“Try to resist cutting anything down that doesn’t need it before the Spring. The seedheads of perennials and grasses such as veronicastrum, yarrows, showy stonecrop, prairie dropseed, oat grasses, switchgrasses and feather reed grasses are exceptional sculptural elements in harsh frosts and in early snows before they are completely inundated in deep late winter snow.”

“Winter watering is often forgotten in the dormant garden. Many shrubs and trees are lost to dry soil and drying winter winds than anything else. Consider your plant selections carefully and pay attention to those that still need some winter moisture to emerge healthy and thriving in the spring.”

“Contrast tends to be the most dramatic tool at our disposal in the winter garden. Consider a chartreuse Pfitzer Juniper or the yellow twigs of a Yellow Mountain Willow against a backdrop of deep green pines. These garden components will catch the eye even in the darkest months of winter.”

“Use deciduous trees and tall shrubs to protect south facing outdoor spaces. This will provide shade and cool temperatures in the summer and allow the warming sun in during the winter months.”

 

SOME GREAT WINTER CHOICES

Cornus argenteo marginata – An excellent choice as it is one of the reddest of the red twig dogwoods in winter yet provides outstanding summer interest with attractive variegated foliage and the ability to thrive in full sun.

Ilex and other structural evergreens stand up well to heavy snows provide robust structure with or without snowy conditions.

Rosa rugosa – Large red rosehips in the winter provide great interest in natural gardens.

Japanese Maples –The twisted and contorted branches of Japanese maples provided an unprecedented living sculpture to gardens. Best placed on the north side of buildings where protected from winter sun and wind. There are many cultivars being grown by nurseries that combine Korean and Japanese Maples for a combination of hardiness and aesthetics.

Tsuga canadensis spp. – Canadian hemlock come in many shapes and forms and provide an excellent alternative to junipers.

Acer griseum – Paperbark maple. When grown in and amongst the white bark of aspen trees, this ornamental tree with a cinnamon colored peeling bark adds another dimension to a garden in the winter.

Polystichum and Polypodium –  (it’s called a Christmas fern, after all!) In broad swaths ferns can add tremendous texture and pair well when punctuated by the broad seed heads of a yarrow or a tall stonecrop.

Drumond, Coyote or Yellow Mountain Willow are good choices for nice yellow coloring on their new growth and early spring catkins. The Dwarf Arctic Willow with purplish branches and early spring catkins doesn’t have its counterparts yellow coloring but makes up for with it a very graceful arching habit.

Fruiting shrubs and trees have no rival to the color they bring in the winter garden as well as the year-round food for birds that are brave enough to stick out the winters (yew, crabapples, snowberry, etc.).

Hedra helix – English Ivy and other ivy while having been used for years for winter garden interest, we caution you to use tools such as The Plantium to verify noxious status in your area! These plants are often still commercially available even while state’s work to list them as noxious and invasive!

With nearly 2,000 plants showing with the ‘winter interest’ filter, The Plantium can help you with designing with winter interest plants in your garden!

Designing with Bulbs

We’ve all read some great articles about designing with bulbs (and corms) so why not keep the discussion going? Designing with bulbs can be daunting. Visiting the botanic gardens in spring nearly blinds us with the glory of huge swaths of spring bulbs. Vast beds of daffodils, crocus and tulips are the sure sign that spring has sprung. A bed of crocus dusted with snow is an iconic image of early spring. Now let’s focus our attention on some other aspects of designing with bulbs, year-round interest and designing to specific bloom heights.

5177_WPFL_Eremurus-himalaicus-WMC_001Dahlia 'XXL Veracruz' AZTEC

The opportunities presented by designing with bulbs can be taken advantage of year-round with a little planning and great execution. Gladiolus and Dahlias can bring in a huge color punch during the mid-summer to late summer in warmer climates and similarly Allium and Autumn Crocus in colder climates. Similarly, lilies can provide a tremendous amount of foliar interest in the early summer months and then finish the season off with splendid color in late summer and even through the fall. The first step is to sort through the vast array of choices in bulbs and corms and remember what you are trying to achieve. Here a sampling of a season-long list for a garden in zone 6a, that’s scented, and attracts bees, hummingbirds, and butterflies. This short list from The Plantium yields plenty of choices to keep you thinking about designing with bulbs all season long! There are so many more to choose from!

Bulb Flowering Season

The next consideration is careful planning around bloom height. This same list now includes plant (foliar) height vs. actual bloom height. Not planning for the bloom height of late blooming bulbs is a common mistake. Some height variations will be minimal but some can be more than a foot or even up to 4’! Check out the Foxtail Lily. Many of these bulbs are not known for lush foliage so you can place them further back in the garden (than you might normally based solely on foliar height) with other perennials or shrubs around them. This leaves their bloom to surprise us when the time is right!

Bulb Flower Heights

Planting Under Evergreens

OK, technically this is a designing and planting UNDER evergreens (not WITH evergreens) but let’s roll with it. “Why won’t anything grow under this spruce!” Try planting under a pine, fir, or any other large needled evergreen, and you get a universal refrain echoed by professionals and garden enthusiasts all over the country. This blog explores the reasons plants won’t grow under your conifers, and what you can do to create a beautiful landscape when planting under and around mature evergreens.

First we’ll explore the most popular assumption as to why nothing will grow: “The soil is too acidic (or toxic?)!”

Let’s put toxic to bed right now. It is flat out not true. A myth. Now many others believe conifers acidify the soil around them through needle drop to the point where no other plants will thrive. It is true that the soil around conifers is often acidic. As a general rule, conifers prefer more acidic soils, and if you see a large, healthy needled evergreen you can usually assume some level of soil acidity. It is also true that, over long periods of time, some species of conifers acidify the soil around them through needle drop especially if the pine needle duff is allowed to decompose and is not cleared out each spring.

Planting under evergreens bares all

A natural pine duff layer

But let’s take a moment to review the pH requirement of many evergreens in comparison to the pH requirements of most ornamental landscape plants. Although they can often withstand more acidic soil, the ideal pH for Norway spruce, Fraser fir, Canaan fir, Scotch pine, White pine, Douglas fir, Blue spruce, and Concolor fir is between 5.5 to 6.5. This jives fairly well with the average range of 5.8 to 7.0 for most ornamental landscape plants!

Here, just as in the rest of life, it is important to never assume. Always test your soil before pinning the blame on low pH! You can make some amendments to the soil to bring the pH up a little while still maintaining it in the acidic range that your evergreens will love.

Regardless of soil pH, there are likely three other tricky factors at play under your tree: Shade (possibly very deep shade), dry conditions, and nutrients. The dry conditions are due to two factors. First, the dense canopy creating the shade also prevents much water from reaching the ground directly under the tree. Second, up to 75% of feeder roots for the tree are in the top 12” of soil. These roots are competing intensely with any other plants for available moisture and nutrients.

So to counter these challenges, you must create the dreaded DRY SHADE GARDEN! Any internet search will reveal that dry shade garden plants are about as easy to find as the holy grail.

So before you charge ahead, ask yourself one more time: do you REALLY need to plant under that evergreen, or can you plant around it and neatly mulch the area directly under the tree? If you decide you really must plant, get ready to tackle the last hurdle: extensive surface roots!

The surface roots from your tree can make it very difficult to dig in new plants. Adding planting soil on top of tree roots can kill a tree, so the best bet is to buy the smallest plants available and dig them in individually around the roots. Apply 2” or so of mulch (never more than 4”, as deeper mulch could be detrimental to the tree), and water your new plants very well at least for the first growing season, or until it looks like they are holding their own. In drier climates of the country you can probably count on ALWAYS having to maintain irrigation under the evergreen tree to make sure even the dry shade plants thrive. It is a delicate balance, however, as overwatering in the shade and developing fungus and root rot issues is a common misstep.

Finally, this still does not tackle your final challenge of nutrient competition. A large, healthy evergreen is sucking up a significant amount of the nutrients in the soil. By committing to planting directly under the tree you are committing to a constant refresh of the plants every few years as they run low on nutrients and cannot compete with the large tree OR you are committing to a CONSISTENT regimen of soil amendments. Either way, these gardens will require serious nurturing.

The Plantium is a great resource to quickly spec dry shade plants for your project. Another way is to just head out to the woods and check out the natural understory in your area! Lastly, botanic gardens and the agricultural extension for your area are great sources for dry shade plant recommendations.

Conquering planting under evergreens

What success looks like!

Designing with Cactus

What is a Cactus?

Many people, even those who consider themselves familiar with arid plants, get confused when it comes to what really constitutes a cactus. Isn’t it basically anything spikey that grows in dry climates? No! A cactus is, in fact, a very specific thing.

Cacti are members of the family Cactaceae. There are approximately 1,800 species of cactus.

Two specific things set cacti apart from other plants:

  • Not all cacti have spines when they mature, but a great way of distinguishing a spiney cactus from other spikey plants in the field is the presence of “areoles,” little bumps on the plant from which clusters of spines grow. If the spines on the plant are not growing in clusters out of these bumps it’s not a cactus!

Cactus aerole

  • All cacti also have a specific flower structure. Though the flower of each cactus species may be very different, all cactus flowers have many tepals (a term used when the sepals of a flower are indistinguishable from the petals) that are somewhat fused; hundreds of stamens; and many-lobed stigmas.

Yellow prickly pear cactus flower

Designing with Cacti

As a group, cacti are drought tolerant and are a great option for any water-conscious landscape. But xeric gardens aren’t the only ones that can benefit from the use of cactus! Their frequently strong sculptural or geometric forms and punchy colors can add punctuation to any landscape design, as long as the growing conditions are right.

Cacti with upright or twisting forms are popular for use against a striking backdrop such as a richly-colored wall, or for their silhouette against a vista. They can also be grouped together for great large-scale textural effects, or consider pairing their chunky forms with something soft such as Mexican Feather Grass (Nassella tenuissima) for inviting contrast. Barrel cacti are perfect for creating rhythm and reinforcing patterns in design, and the bold textures and colors of pad cacti (Opuntia) provide great backdrops or focal points in the landscape.

Agaves, other succulents, and grasses are great design companions, but cacti can really be added to any composition with complimentary leaf colors, contrasting textures, and similar environmental requirements.

Most cacti are very sensitive to over-watering, so make sure the soil is very well drained, and the other plants in your design have compatible water use requirements. Use The Plantium to easily find great cacti and appropriate design companions for your next project!

Fun Facts about Cacti

  • All cacti are succulent, but not all succulents are cacti!
  • All cacti are native to the Americas, though they have spread around the world post-colonization.
  • Although they are typically slow growers, cacti are very successful in arid climates, so much so that in certain countries like Australia many cacti are considered noxious weeds.
  • Cacti grow in a wide variety of places, though mostly in habitats that experience some drought. People associate cacti with hot climates, but there are many species that are hardy to -30 deg. F and lower!
  • Cacti come in a wild variety of shapes, sizes, and forms, from the stereotypical Saguaro, barrel, and prickly pear, to the Rose Cactus (Pereskia grandifolia) which looks like a tree or shrub at first glance.
  • Most cacti don’t have true leaves, instead performing photosynthesis in their modified stems. However some cacti, like the rose cactus, can be very leafy!