Showing posts with label Favorite Plants. Show all posts
Showing posts with label Favorite Plants. Show all posts

Tuesday, August 9, 2011

Canna lilies

Canna 'Tropicana' foliage
Cannas (members of the Cannaceae family) are not actually lilies, but for some reason unknown to me, that's what people call them. I just call them beautiful. Their big, colorful leaves remind me of banana trees and their exotic flowers make me think of the tropics.

Even if Cannas never flowered, their variegated foliage would make them worth growing. Look for the green-yellow variegation of 'Pretoria', as you see above, or the red-yellow-pink-green leaves of 'Tropicana' at top. Others like 'Red King Humbert' and 'Wyoming' have mahogany leaves.

Dwarf varieties get 18" to 3 feet tall. Standard varieties reach 4 - 6 feet tall.

Canna flowers may be yellow, orange or red.

In Seattle, cannas are most often grown as annuals. They will over-winter in mild years, but the past few have been too cold for many to survive. Cannas do well in containers and as focal points in mixed borders. When they are blooming, they're a sure sign of summer in Seattle.

Thursday, July 28, 2011

More Smoke Trees

One of the most popular posts on this blog has been the article on purple smoke trees (Cotinus coggygria, vars. 'Purple Robe,' 'Royal Purple,' and others). These trees are in bloom, covered in puffs of "smoke," right now all over Seattle. But did you know that smoke trees come in colors other than purple?

I recently had the good fortune of discovering a golden version of the smoke tree growing next to a purple one. I do not know the specific name of this cultivar, but 'Golden Spirit' (C. coggygria 'Ancot') is one seen often in the trade.

Here is a close-up of its stunning gold foliage, with a few small puffs of smoky bloom beginning to show. The chartreuse leaves have dark green veination, adding to the visual interest. This is a good plant to keep in mind when you are wanting to use foliage color as a design element.

This is a green form of Cotinus, possibly a variety called 'Pink Champagne.' The pink puffs are interesting, though this plant is certainly not as dramatic as the purple or gold versions.



All Cotinus varieties are drought tolerant and do best in poor, even rocky, soils. They are noted for their fall color, brilliant yellows through red-orange.

Wednesday, July 27, 2011

Himalayan Honeysuckle

Himalayan honeysuckles (Leycesteria formosa) are in bloom right now in Seattle. You can't miss them, with these stunning flowers.
The actual flowers are these little white bells that you see above. The showy purple bracts that surround them are what catch your eye. These flowers will give way to berries (you can see a little red berry starting to form in the photo above) that are popular with birds. The berries start out green, turn red and then finally, black.
Himalayan honeysuckles are shrubs not vines, as are typical honeysuckles (Lonicera sp.) They grow quickly to fill a space 6' x 6'. In particularly cold winters, you may see significant die back on these plants. But don't give up on them right away. Cut away the dead branches and wait a bit. They are vigorous plants and often come right back when the weather starts to warm and the days are longer.

Friday, July 22, 2011

Hooked on Heuchera

Heuchera (pronounced HOO-ker-ah), also called coral bells, is a popular perennial in Seattle gardens. Each year, it seems, there are several new introductions to the collection available at nurseries, adding an ever wider selection of color and texture.
Some of the most familiar forms of this plant have purple leaves, as does this one above. Tiny, bell-shaped flowers are borne on tall slender stalks above the foliage in early summer. But it is the foliage that is the true star of the show, adding mounds of color nearly year around. In the purple range, look for varieties such as: 'Chocolate Ruffles,' 'Chocolate Veil,' and 'Garnet.'
Some varieties of Heuchera are noted for their veination patterns. I believe the variety shown above is called 'Pewter Moon.' Look also for 'Ruby Veil,' and 'Ring of Fire' to see other variations on the theme.
In recent years, Heuchera varieties with golden leaves have become very popular. Look for varieties such as 'Southern Comfort,' 'Peach Flambe,' and 'Caramel.'

Heuchera are easy to care for. Cut back ratty foliage in late winter, very early spring and a new flush of colorful growth will soon emerge. Because of the range of leaf colors and textures, these are good plants to keep in mind when you are designing a garden. Repeat the same plant 3 to 5 times throughout the garden, to draw the eye through the landscape, and to complement other colors in the garden. In Seattle, you often see Heuchera planted in mixed borders, containers and rockeries.

Tuesday, June 7, 2011

Viburnums

Some of these shrubs are David's and some are Marie's.
Others are known as Spring Bouquets or Snowball Trees.
Some have names like Korean Spice, Pink Dawn, and Highbush Cranberry.
Some are tall. Some are short. Some are evergreen. Some lose their leaves in a fiery display in fall.
Despite their differences, what these all plants have in common is that they are members of that large group of shrubs called Viburnums.

One of these in bloom now in Seattle is the Common Snowball (Viburnum opulus 'Roseum'). One look at these perfectly round clusters of flowers and you see where this plant got its common name. These shrubs can be trained into small trees, 8-10' high and 10-12' wide. Fall color is stunning most years, with those maple-like leaves turning deep rusty red.

My landscape design instructor used to say, "The trouble with common plants is that they are used commonly." I think of that quote when I see bedraggled specimens of David's viburnum (Viburnum davidii) used to edge the parking lot of a strip mall. These handsome evergreens deserve better treatment than they often get. With deeply textured, dark green leaves, a row of these shrubs make an attractive low (3-4') hedge. In spring, clusters of white flowers open from those pink branches you see above. The flowers are followed by iridescent blue berries in fall. V. davidii does very well in our acid soils and tolerates partial shade.

With very little care, these plants offer great reward in the landscape. I'm afraid that gardeners often avoid using them because they've only seen them used "commonly." I encourage you to explore some uncommon uses for this plant.

It probably comes as no surprise that I am partial to the viburnum that shares my name, Marie's viburnum, also called Doublefile viburnum (V. plicatum tomentosum 'Mariesii'). You can see this plant in bloom all over Seattle right now. Alas, I do not have room in my little garden for this shrub which gets about 10' tall and spreads a good 10-12' wide.
Here's a closer look at the flowers. Row upon row of these lace caps make this one very showy plant in spring. In fall, the leaves turn brilliant red before they drop.

Of course these are only three of the viburnums that grow in our area. Look also for V. x bodnantense, V. carlesii, and V. tinus. To learn more about these versatile and beautiful shrubs, I recommend Michael Dirr's book, "Viburnums: Flowering Shrubs for Every Season." (Actually, anything on woody plants written by Dirr would be a good addition to your gardening library.)


Monday, May 23, 2011

Ceanothus

Ceanothus, also known as California wild lilac, is starting to bloom now in Seattle. Its striking, purple-blue flowers are shaped like tiny bottle brushes, thus inspiring the common name.

There are many varieties of Ceanothus, but few are hardy enough for our climate. Most are native to California where, after a wet winter like this past one, the coastal hills are covered in a blue haze of bloom in the spring.

The most common variety of Ceanothus grown in Seattle is the one shown above, Ceanothus impressus or Santa Barbara Ceanothus. If you add one to your garden, be sure to give it plenty of room - it can easily get 10 feet tall and 10-15 feet wide.

Flower color among the varieties can range from white (which is rare), through pale blue, to deep purple-blue. When choosing one for your garden, as always, buy plants in bloom to be sure of what you are getting.

Ceanothus plants are generally drought tolerant, needing a bit of supplemental watering the first couple of seasons while they get established.

There are a couple of Ceanothus ground covers that are grown in our area. Point Reyes (C. gloriosus) has glossy, dark green, holly-like leaves, with light blue flowers, and can get as tall as 18", with a spread (if it is happy) of 12 to 16 feet.
The most striking Ceanothus ground cover is 'Diamond Heights,' (C. griseus horizontalis 'Diamond Heights') shown above. It does not look anything like its relatives until small, pale blue flowers appear in late spring. But flowers are not the reason to plant this beauty. You'll want this in your garden because of the foliage - those yellow-green leaves with splashes of dark green in the center are a joy to behold.

Unfortunately, we've had some very cold weather the past three or four winters and this ground cover has not fared well. My once-thriving 'Diamond Heights' specimens have all been killed by the cold. However, that doesn't mean you should give up on this plant. Just treat it as an annual, tuck it into containers and let it spill over the edges.

Rockery Plants - Part 2

OK, here's Part 2 of our virtual plant identification tour of Seattle rockeries.
This is Bergenia crassifolia, or winter blooming bergenia. It is also called "pig squeak" because the leaves make a squeaking sound if you rub them when they are wet. This is an evergreen perennial that requires little care. Just cut away old or cold-damaged leaves and faded flowers to keep it tidy.

These chartreuse flower heads belong to Euphorbia (I'm guessing this is a young specimen of E. chariacias wulfenii) a large genus of plants that includes the poinsettia (E. pulcherrima). Be careful handling these plants. They have a milky, white sap that is very irritating to the skin - I always wear rubber gloves when working with them, having been burned (literally!) in the past.

Along with them, a collection of English bluebells have taken up residence. Rarely planted on purpose, you'll find these cheerful blue flowers in gardens and rockeries everywhere in Seattle.

Speaking of blue flowers, these are grape hyacinths (Muscari sp.) These also happily multiply wherever they are planted. The red plant below them is a variety of Sedum.

Of course, rockeries are not all planted with ground covers and small perennials. When the planting pockets are large enough, small trees and shrubs can do quite nicely. Here at the top of the rockery is a weeping Japanese maple (Acer palmatum 'Dissectum Atropurpureum'), below it is David's viburnum (Viburnum davidii), and at the bottom, lavender (Lavandula sp.) is blooming.

Rockery gardening can be challenging because the planting spaces are often quite small and they dry out quickly in warm weather. Watering can be difficult because the force of the water stream can wash away some of what little soil is there. But after some trial and error, you will find a planting combination that will thrive with a minimum of care.

Missed the first part of the tour?
Go back to Part 1.

Rockery Plants - Part 1

As I said in my post on retaining walls and rockeries, Seattle is a city built on hills. Those hills are terraced with miles and miles of rockeries, which are planted, both accidentally and on purpose, with thousands and thousands of plants. Many of these plants bloom in spring, lining our streets with mini-explosions of color.

If you have ever wondered what any of these plants are, I'm here to help. In the next two posts, I'm going to take you on a little virtual tour of Seattle rockeries to help you identify some of the many plants you see blooming there this time of year.
This is a classic rockery plant combination: yellow Alyssum 'Basket of Gold,' paired with purple Aubrietia deltoidea. Aubrietia comes in both dark and lighter shades of purple; less common is a variety with deep rose colored flowers.

Candytuft (Iberis sempervirens) is a tough perennial with a long bloom time. It's one of the true bright whites (along with shotweed flowers) that you see early in the season. If you have this plant in your rockery, be sure to shear it after blooming to keep it from getting leggy. 

The red and green succulent plant spilling out onto the stairs is one of the many varieties of Sedum available in our area. Sedums are particularly well suited to life in a rockery because they require very little in terms of water, nutrients and care. 

The pink flowers on the left are heather (Erica sp.), the medium blue flowers in the middle are Lithodora, and the light blue flowers at right are periwinkle (Vinca sp). As with candytuft, all three of these should be sheared or cut back after blooming to keep them compact. In the lower left corner, new fronds, called fiddleheads, are emerging from a fern. To keep ferns looking tidy, cut away old, dried out fronds in late winter/early spring.

Wait! There's more:



Friday, May 20, 2011

Picking Out the Pines

Do you have trouble telling one conifer from another? Do pines, cedars, firs and spruces all look the same to you? Well, after you read this post, you'll be able to tell the pines, at least, from all the others.

Here's how: pay attention to evergreen trees in your neighborhood this week. You'll notice that some of them have new shoots emerging from the tips of their branches that look like fingers pointing toward the sky.

These shoots look as if the tree is making the kind of rude gestures that humans do when they've been cut off in traffic. But don't take this personally, because these "fingers" are simply the beginnings of this year's growth for the pine tree. No other conifer produces shoots that look like these, so when you see them, you know the tree is a pine.

Over the next few weeks, these shoots, called "candles," will grow longer and shortly after that, new needles will appear along them. Depending on the type of pine, this will add anywhere from one to eighteen inches to the size of the tree.

You'll notice that some pines have white candles. (My guess is that these white shoots are what inspired people to start calling them candles.)

And that some have yellow candles. But they all work the same way.

You can shape a pine tree over the years by pinching the candles to stop or slow the growth of a branch. If you don't want a branch to add any new growth for the year, cut the candle completely off. If you want it to add some growth, but not too much, cut off just a portion of the candle. This technique is used in formal Asian gardens to train pines into a specific shapes.


As a bit of pine trivia, you might be interested in the fact that pine trunks offer a sort of record of the amount of rainfall from year to year. If you look closely at the tree on the left, you can see that there's bare trunk for several inches, then a whorl of branches, then more bare trunk, another whorl of branches, and so on. The distance from one whorl to the next is one year's growth. In rainy years, the trees grow more and the distance between whorls is longer; in drier years, it is shorter.





There are many pine varieties that grow well in the Seattle area. If you want to know more about them, the Sunset Western Garden Book has a lengthy section on types, growth rates, habits and more.

Friday, May 13, 2011

Favorite Plants: Solomon's Seal

One of my favorite woodland plants is beginning to unfurl in my garden right now. It is Solomon's Seal (Polygonatum odoratum).

This herbaceous perennial (herbaceous meaning that the foliage dies down in fall; perennial meaning that it comes back year after year) is always one of those great surprises in the garden in spring. Even though I know where it is planted, it is astonishing to see it rise up out of the ground in just a matter of days, from little pointy "noses" barely poking out of the soil to 4 foot tall arching stems.
The underside of the stems is lined with double rows of bell-shaped flowers that are slightly fragrant. The flowers fade in time, but the arching stems continue to grace the garden until late October, when the leaves turn yellow and fall, and the stems die back.

Solomon's Seal likes shady, woodland garden settings. The cultivar, 'Variegatum,' has white edges on the leaves and its stems are dark red when they first emerge.

This plant spreads via underground rhizomes. To propagate, divide clumps in early spring. You'll need a sharp shovel for this job, as the root/rhizome balls are dense.

This plant is in the same family (Liliaceae) as the Northwest native, False Solomon's Seal, but not in the same genus. If you are looking for the native at local nurseries, the botanical name is Smilacina racemosa. The plants are easy to tell apart when they are in flower. False Solomon's Seal has a conical spray of tiny white flowers at the end of each stem and no flowers under the stems. Without flowers, the plants look very similar.

Monday, April 25, 2011

Daphne

We've had an unusually long and cold winter in Seattle this year. So when my beloved 'Carol Mackie' daphne began blooming this week, I was thrilled. The sweet scent of her flowers is a sure sign of spring.

When I moved into my house 9 years ago, I found this plant nearly dead in the front yard. It was barely 6 inches tall and looked so sickly that I almost tossed it into the compost bin. But with a limited plant budget at the time, I thought it was worth trying to save. So I dug it up and moved it into a protected area in the back garden, where it has been living happily ever after. It is now about 4 feet tall and wide, and would be bigger, except that I prune it each year after it blooms to keep it from overtaking the walkway.

Hundreds of tiny pink buds on this Daphne 'Carol Mackie' will open gradually over a 3 to 4 week period, depending on weather, filling my back garden with fragrance. 

My daphne (formally known as Daphne x burkwoodii 'Carol Mackie') is not as common in Seattle gardens as Daphne odora, or winter daphne. Winter daphne blooms earlier in the year, usually in February. You will find several wonderful specimens in the Witt Winter Garden at the Washington Park Arboretum.

Although daphnes are popular shrubs in the Northwest, they have a reputation for being fussy. They can be planted with all the loving care and attention you can muster, and yet fail to grow. They don't like soil that is too wet, but they don't like to dry out, either. They seem to be doing well, then suddenly, without warning, die.

There is a trick, however, that you can use to increase the odds of your daphne's survival. I've been using this trick with great success for almost 20 years. It is simply this, plant your daphne near a concrete walkway or (better) throw a couple of pieces of concrete rubble into the planting hole. That's what I did with the happy plant you see above.

Why does this work? The soils in the Northwest are acidic, perfect for acid lovers like rhododendrons, azaleas and blueberries. But plants like daphne, that prefer more alkaline soil, struggle. The lime contained in the concrete leaches into the soil a little bit each time it rains or when you water. That lime sweetens the soil around your daphne slightly, making for a happier plant. And when Daphne is happy, she brings beauty to your garden.

Tuesday, April 19, 2011

Magnolia Stellata

In Latin, the word "stellata" means starry. (For more on Latin botanical names, look here.) Knowing this makes it easy to identify this small, shrubby member of the Magnolia family. Instead of the well known, cup-shaped flowers magnolias are famous for, this lovely little tree has flowers that look like stars.

In bloom right now in Seattle, these Star Magnolias are wonderful additions to small gardens and mixed borders. There are several varieties, all deciduous and slow growing. They can reach 10- 20 feet high, with a spread from 10- 20 feet. Be sure to check plant labels for specific sizes before you buy one.

These trees add interest to the winter garden with a profusion of fat, fuzzy flower buds that resemble pussy willows. The buds open in early spring with flowers that light up the landscape and, depending on the variety, scent the garden with a light fragrance. Most trees have white flowers, but there are pink forms as well.

As with all flowering plants, it is best to buy them in bloom to be sure you get the color and fragrance you want. If you can, plant this magnolia where you can see it from your window because it is truly one of the stars of the spring garden.

Tuesday, October 26, 2010

Sweet And Sour Fall Color

We are having a particularly rainy and windy fall in the Seattle area this year, but don't let that keep you from enjoying the vivid colors of the season. For example, look for two of my favorite trees for fall color: Sweet Gum (Liquidambar styraciflua) and Sourwood (Oxydendrum arboreum).

Native to the eastern US, sweet gums are attractive trees that can grow to 60' tall, 20-25' wide. They are sometimes mistaken for maples because their leaf shape is similar.
In fall, these leaves turn color in multiple shades: burgundy, red and yellow. Certain cultivars, such as 'Festival' and 'Roundiloba' are especially showy with bits of peach and orange mixed in with the purples, reds and yellows. These trees are stunning! If you are fortunate enough to pass one on your daily rounds, watch as the leaves progress through color changes as the days go by. They'll take your mind off the rain.

Sourwoods are also native to the eastern US. They are much smaller than sweet gums, taking several years to reach a height of 20 - 30', making them good trees for urban yards. I don't think they are planted nearly enough here. They are well suited to our acid soils and cool summers.
Sourwood leaves remind me of fruit tree leaves, like apples or peaches. But in fall, unlike the leaves on fruit trees, sourwood leaves turn brilliant red, orange and black-purple. The display is even more of a head-turner because in late summer, and early fall, these trees produce drooping clusters of white, bell-shaped flowers. (They are in the same family, Ericaceae, as the Strawberry tree.) These flowers make sourwoods easily identifiable this time of year. They are said to be fragrant, so get up close; fall breezes quickly carry the scent away.

In spite of rain and blustery weather, this is a good time to get outside and observe the change of seasons. In the Northwest, we are blessed to have a huge variety of trees with different growth habits. We have longer, more colorful autumns than other parts of the country because as one group of trees fades, another begins to color up. Most years, this means that we have close to three months of color. Enjoy it!

If you live in the city of Seattle and need a good tree guide, consider Arthur Lee Jacobson's "Trees of Seattle: The Complete Tree-Finder's Guide to the City's 740 Varieties." This book has become a classic, and for good reason.

Monday, October 11, 2010

A Rose Is a Rose, Is an Apple, Is a Berry

Botanically speaking, roses belong to the Rosaceae (ro-ZAY-cee-ee) family. This is a huge family, encompassing over 2800 species of plants, including fruit trees, shrubs, berries and, of course, roses. There isn't a single set of characteristics you can use to identify all members of this family, but there is one identifier that several genera share: a star-like shape at the base of the fruit.

Here you see cotoneaster berries with those distinctive "stars" on the bottom.

Once you know to look for this characteristic, you will begin to recognize other relatives in this family. These include: Hawthorn, Pears, Rowan, Cotoneaster and Pyracantha.

Fall is the best time of year for this, of course, because that's the season when these fruits are ripe.

Here you see the "star" at the base of an apple, another rose relative. You'll find stars on the bottoms of pears, too.

And notice the stars on rose "hips" this time of year.  (Pictured here are Rosa glauca hips.)

Beyond this bit of botanical trivia, it is useful for gardeners to be aware of these family relationships. Many members of the Rosaceae family share a susceptibility to fungal diseases, such as black spot on roses and scab on apples. Knowing this, a gardener can be prepared to take steps to keep plants healthy, which might include the use of dormant oil sprays, good sanitation practices and companion planting with members of the allium family (garlic, chives, onion, etc.)

So there's your mini botany lesson for today. Now go out and do your own version of "star search."

Tuesday, October 5, 2010

Strawberry Trees Forever


Is it a tree? Is it a shrub? With the right cultivar selection and a little artful pruning, it can be either. The standard species form of a Strawberry Tree (Arbutus unedo) can grow to nearly 30 feet tall and wide. If it is limbed up as it grows, it can look like this.
If you want a smaller version, choose cultivars like 'Compacta', which will get to about 10' x 10', 'Oktoberfest' to about 8' x 8', or 'Elfin King' about 5' x 5'.
Whichever one you choose, you will be rewarded with year-around interest. Strawberry trees have glossy, evergreen foliage.  Large clusters of white, bell-shaped flowers appear in spring and, depending on availability of moisture, continue to bloom until fall. (The foliage, flowers and stems may look familiar to you if you live in the Pacific Northwest because strawberry trees are related to our native Madrone, Arbutus menziesii.) Flowers are followed in the fall by fruit that starts out looking like citrusy gum drops (see below).
As it ripens, the fruit begins to look like strawberries; hence the name, strawberry tree.
This fruit is edible, but bland. Even the birds will ignore it (an advantage from an ornamental point of view) until the tastier seeds and berries in the garden are gone.

Strawberry trees are wonderful choices for small gardens. They aren't fussy about soil. You can choose a cultivar that will fit the space available. They will tolerate some shade, although, like most plants, will flower and fruit more readily in sun. They can be shaped easily with light pruning.

Strawberry trees in the Seattle area are particularly full of fruit this fall. They are a unique addition to the autumn color palette that is so spectacular and long-lasting in our area.

Wednesday, September 8, 2010

Trumpet Vine, the Last Blast of Summer

As the first day of autumn is rapidly approaching and most of the blooms in the garden have faded, my trumpet vine is flowering with an exuberance that is positively spring-like. Trumpet vines (Campsis radicans) are vigorous plants that typically scamper up to 40 feet or more in just a few seasons. They cling to arbors and walls with aerial roots.


Most trumpet vines sport red-orange tubular flowers as you see above, but there are a few newer cultivars, such as one called 'Flava,' that have yellow flowers. Much loved by hummingbirds and bees, these vines attract wildlife and pollinators to the garden. (To learn more about landscaping for wildlife in our area, check out "Landscaping for Wildlife in the Pacific Northwest," written by Russell Link, wildlife biologist with the Washington Department of Fish and Wildlife.)

In some parts of the country, trumpet vines can be invasive, but I have not found that to be the case in the Seattle area. Vigorous pruning may be required to keep a vine in bounds, but that's only necessary once, maybe twice, a season.



Wednesday, July 21, 2010

Daylilies

Daylilies are called daylilies because each flower is said to last only a day. Although the flowers look like true lilies (Lillium sp.), daylilies are in the Hemerocallis family. If you have trouble telling them apart, simply look at the stems and leaves.
Daylilies have long, strap-like leaves, with flowers borne on long, leafless stems. True lilies are bulbs with a single long stem. True lilies have leaves along the stem.

Daylilies come in many colors and sizes and are among the hardiest of perennials. They aren't terribly fussy about soil, but, of course, will do best in beds with good drainage that have been amended with organic material. Water during dry spells.

In the northwest, plant or divide daylilies in early spring or fall. Clumps will spread over time and for best bloom should be divided every few years.

Most daylilies bloom late spring early to mid-summer for a period of days to a few weeks depending on weather. A few will bloom throughout summer, such as this charming yellow, dwarf variety called 'Stella d'Oro.'

For more information on daylilies, take a look at Diana Grenfell's book "Daylilies," part of the Gardeners Guide series.