Bluebeard – Caryopteris spp.
Plants that bloom late in the summer and into fall are particularly important in the garden. Not only do they offer continuous color and interest as other plants fade, but they provide essential nectar and pollen resources to bees, butterflies, and other beneficial insects as they prepare for migration and hibernation. One such late season bloomer is Caryopteris.
Firecracker Vine – Ipomoea lobata
After months of growth, Ipomoea lobata is finally coming into its own. Commonly known as firecracker vine, Spanish flag, or exotic love vine, this annual, ornamental vine can be a real showstopper when it finally reaches full bloom.
Mexican Sunflower – Tithonia rotundifolia
Mexican sunflower is a real presence in the garden. Closely related to the sunflower genus (Helianthus), Tithonia rotundifolia matches many sunflowers in its size and showiness – reaching up to six feet tall and four feet wide in a single season and producing dozens of large, orange to red flower heads. The flowers occur from mid-summer into the fall and are similar in appearance to many other flowers in the aster family. It is native to Mexico and Central America, but is easily grown as an annual in cooler climates.
Joe Pye Weed – Eutrochium purpureum
Native to wooded slopes, wet meadows, thickets and streams of the eastern and northern United States, Joe Pye weed is better known as a garden plant in England than here in its homeland. Stunning in size (4-7’ tall) Joe Pye weed is an impressive plant of the aster (Asteraceae) family whose stout, arching stems are awhirl with large serrated leaves and topped with domes of small flowers rich in nectar and pollen.
Rocky Mountain Bee Plant – Cleome serrulata
At first glance Rocky Mountain bee plant might appear to be an import from an alien planet. The big pink blooms, with long seed capsules dangling down like legs, atop a spindly stalk are unlike many other plants. So why do we have this plant at the Idaho Botanical Garden? Well, despite its otherworldly appearance Rocky Mountain bee plant is a North American native. It can be found growing from British Columbia all the way down to Arizona and New Mexico.
Hardy Hibiscus – Hibiscus moscheutos
Hibiscus moscheutos has the tropical appeal of other Hibiscus species but is surprisingly well-adapted to survive in cold climates. For this reason it is commonly known as hardy hibiscus. Another common name, swamp rose mallow, refers to the wet environments where it is found growing naturally. Its native range spans from Texas eastward to the Atlantic coast and then north into Ontario, Canada. It is a robust, woody perennial in the mallow family (Malvaceae) that reaches up to 7 feet tall and 4 feet wide. Its flowers can be the size of a dinner plate, and its large overlapping petals come in a range of colors from white to pink to deep red, often with a maroon or crimson center. The pistil and stamens form a central column that is prominently displayed. Each flower only lasts a day or two, but new flowers open each day throughout the bloom period which runs from July to September.
Globe Thistle – Echinops ritro
In the Children’s Adventure Garden, a mass of planting of globe-shaped, blue-purple flowers draws a crowd. In the heat of the day, nearly every flower head is occupied by at least one bee, if not three or four. Human visitors are also lured in, not only to observe the swarm of pollinators but also to admire such a unique bloom. The view is other-worldly.
Desert Willow – Chilopsis linearis
The common name for Chilopsis linearis, desert willow, might first appear to be an oxymoron, as we often associate willows with water. However, Chilopsis is only “willow” in name and appearance. True willows are in the genus Salix. Chilopsis, on the other hand, is a monotypic genus – a genus that contains only one species. In this case, that species is Chilopsis linearis.
Native to Mexico and Central America, dahlias are tuberous rooted perennials in the aster (Asteraceae) family. Years after its discovery, the first dahlia was taken to Europe. Although it adapted well to European soils, it did not dependably survive winters. In the 19th century, botanists in the Netherlands began to experiment, and from a pair of dahlias came the majority of dahlias found for sale today.
Purple Prairie Clover – Dalea purpurea
Throughout the Idaho Botanical Garden you may notice certain plants covered in small metal cages made of chicken wire. Curious visitors often ask what we use these cages for, and the answer is: for protection. It really is a problem we have brought on ourselves. While human members see the staggering variety of plants we have here at the garden as a tapestry to be admired, our resident critters see a veritable smorgasbord of tasty treats. One particularly appetizing plant that needs extra protection is Purple Prairie Clover, Dalea purpurea. Without fortification, this plant would surely have succumbed to our rabbit population years ago, the young shoots being especially desirable for their high protein content. Luckily the clover has become more established over the years, and now appears to be at the point where it is not as appetizing, having woodier, thicker stems, and thus in less need of protection.
Texas Red Yucca – Hesperaloe parviflora
It may surprise you that a plant native to central Texas and northern Mexico thrives in Idaho, but it’s true. Hesperaloe parviflora has a condensed native range deep in the heart of Texas, where it tolerates extremely high temperatures and very dry soils. When grown in regions where temperatures drop below zero in the winter and snow piles up around it, it tolerates that too. It’s a tough Texas plant.
Oceanspray – Holodiscus discolor
As we enter the heat of summer, flowers in many parts of the garden are slowly succumbing to the rising temperatures. However, one plant that is flourishing in the Lewis and Clark Native Plant Garden is oceanspray, Holodiscus discolor. A member of the rose family, oceanspray is a northwest perennial shrub that grows 4-5 feet tall with an arching habit. In summer the shrub is covered in green, deeply lobed leaves and sprays of fragrant white flowers. The plentiful, creamy blooms provide a bounty of food for native pollinators.
Butterfly Milkweed – Asclepias tuberosa
Butterfly sightings have become common in the garden these past few weeks. Butterflies are among the most charismatic of insects and are easy to attract to a garden. The key is to provide a wide variety of flowering plants that produce abundant nectar. One such plant is Asclepias tuberosa. Its common name, butterfly milkweed, demonstrates just how appealing to butterflies it is.
Red Hot Poker – Kniphofia uvaria
The common names of plants can often be misleading or nonsensical. However, looking around town at the blooming Red Hot Poker, also known as Torch Lily, the plant seems suitably named. A native of South Africa, Kniphofia uvaria has quickly become a garden staple throughout the world thanks to its striking blooms, love of heat and sun, and its drought tolerance.
Black Beauty Elderberry – Sambucus nigra ‘Gerda’
A Black Beauty elderberry in full bloom is a sight to behold. Black Beauty is a trademarked name for Sambucus nigra ‘Gerda’. It, unlike the straight species, has foliage and young stems that are shades of purple. The leaves are dark, sometimes black in appearance. They are large and divided into 5 – 7 distinct leaflets. The tiny flowers are pink and white and are organized into a flattened, wide inflorescence called a corymb. They give off a lemon scent. Flowering occurs late spring into early summer, after which large clusters of fruits begin to form. The ripe fruits are highly desirable to birds.
Streambank Wild Hollyhock – Iliamna rivularis
This eye-catching, Idaho native is a member of the mallow family (Malvaceae). As its common name implies, it mainly occurs along stream banks and in wet meadows at elevations ranging from the foothills to subalpine zones. It varies in height depending on its location, but is typically between 3 to 6 feet tall. It sends up numerous flower stalks that are loosely populated with large pink to rose-purple (sometimes white) flowers. Its large lobed and toothed leaves resemble the leaves of maple trees or grape vines. The flowers, fruits, and seeds are similar in appearance to its cousin, hollyhock (Alcea sp.), which explains the other half of its common name. In the wild, forest fires encourage the seeds of Iliamna rivularis to germinate.
Lilacs – Syringa vulgaris
Sense memory in the springtime garden can be strongly influenced by the nostalgic perfume of lilac. Does the scent of lilac in the air take you back to your study abroad in Paris? Whitman’s elegy When Lilacs Last in the Dooryard Bloomed, mourning the death of President Lincoln may come to an English major’s mind. I think of the corsage made of lilacs Tress Parke wore to the high school graduation of her granddaughter, Louise, and smile at the memory of a more innocent time.
Owens Valley Penstemon – Penstemon confusus
The western United States is lousy with penstemons. Idaho alone claims at least 43 native Penstemon species. Neighboring states claim similar numbers. It is hard to think of the West without them, which is why Idaho Botanical Garden has made it a point to showcase as many of these plants as we can get our hands on. We currently have around 60 different penstemon taxa (including varieties, subspecies, and cultivars) distributed throughout our gardens. In fact, a small handful of these penstemons are part of a nationally accredited collection through American Public Garden Association’s Plant Collection Network.
Curly Leaf Sea Kale – Crambe maritima
One of our horticulture missions at Idaho Botanical Garden is to showcase plants that are suitable for gardens and landscapes in the Treasure Valley. That is why we maintain various waterwise and native plant gardens. The plants in these gardens are acclimated to our soils and our hot, arid summers. One such garden is our Plant Select Demonstration Garden. Plant Select is a collaborative organization between Denver Botanic Gardens and Colorado State University that aims to bring ornamental plants to the horticulture industry that are reliable, attractive, low maintenance, and suitable for the high plains and intermountain regions. The horticulture staff at IBG thinks highly of the Plant Select brand, not only for their incredible selection of plants but also because their mission is so similar to ours.
Barestem Biscuitroot – Lomatium nudicaule
Lomatiums are among the diverse suite of wildflowers that bloom in the Boise Foothills each spring. Commonly known as biscuitroot or desert parsley, Lomatium is a genus consisting of around 75 species, all of which are found in western North America. There are several species native to our region; the most common include Lomatium dissectum (fernleaf biscuitroot), Lomatium grayi (Gray’s biscuitroot), Lomatium triternatum (nineleaf biscuitroot), and Lomatium nudicaule (barestem biscuitroot).
For many, the beginning of fall is signaled by the appearance of pumpkin spice lattes. But gardeners might take more notice of the rows of mums appearing outside every box store in the valley. If you like mums, but are tired of purchasing them year after year, consider the Aster. As one IBG gardener likes to call them, “the harbingers of autumn,” are just now coming into bloom. Reliable, hardy perennials, Asters provide a burst of late fall color as well as a last stop for pollinators before winter. Asters come in a variety of colors and sizes, and require very little upkeep. The only challenges with Asters are that many are susceptible to powdery mildew and taller varieties can become unwieldy; however, both of these problems are overcome by selecting the right variety.
A favorite variety of Aster here at the garden is ‘Purple Dome’. Aster novae-angliae ‘Purple Dome’ is an all-purpose Aster whose scientific name means “of New England”. Unlike New York Asters (Aster novae-belgii) New England Asters have thick stems and hairy leaves, and are generally taller. ‘Purple Dome’, however, has been cultivated to maintain a low, bushy habit, making it easier to care for than taller asters that might require staking. Covered in deep lavender flowers, this cultivar generally blooms from late August until frost. As an added, bonus, ‘Purple Dome’ is mildew resistant.
Another low grower is Aster x frikartii ‘Monch’. Compact, but resplendent with light lavender blooms all fall, ‘Monch’ typically grows to only two feet tall, making it a perfect plant for a perennial border, and is also resistant to powdery mildew.
Possibly the best thing about Asters is that, to keep them looking their best, they need to be divided every two to three years; this means, of course, free plants! After your initial purchase, you will have access to a continual supply of these hardy perennials forever!
If you want to learn more about dividing plants, come to our education class, “Divide and Conquer” at IBG on September 29th.
If you’re in search of an Intermountain native option in the world of Aster, Machaeranthera canescens, commonly known as hoary tansyaster or hoary aster might be just what you’re looking for. It is a highly variable species that occurs throughout the western portion of North America as well as in some north central states. It can be found in a wide variety of habitats, and is particularly common in dry and/or disturbed sites, shrub steppes, and meadows. It is native to the Boise Foothills and is one of the few late summer flowering plants in this region. It is considered a short-lived perennial, but it often acts as an annual or biennial. Its latin name “canescens” refers to the small, gray hairs that cover its stems. Its leaves are long and narrow and often have sharply toothed margins. Flower heads appear singularly or in multiples at the ends of branches. A series of small, light green bracts form a cup below each flower head. The flower heads consist of disc florets that are a striking yellow color and ray florets that are pale to dark purple.
Hoary tansyaster can be found throughout the Lewis and Clark Native Plant Garden, as well as in the Foothills Native Plant Garden, along the Wilderness Trail, and in our restoration areas.
So, if you’re looking to get more bang for your buck year after year, and desire a more naturalistic option than mums, consider choosing an Aster. You’ll love the color it adds to your fall garden, and the pollinators will thank you, too!
Maximilian Sunflower is an herbaceous perennial native to the Great Plains regions of central North America. It is usually found in dry open areas such as prairies and bluffs. Helianthus maximiliani is hardy in zones 4-9 and grows 3-10 feet tall and 2-4 feet wide. Maximillian Sunflower is in the Asteraceae family and has a yellow composite flower which consists of disk and ray florets. It flowers August through September and reseeds freely. Cut it back after it flowers in the fall if you want to minimize reseeding. Maximillian Sunflower has long narrow leaves which are alternate, coarse, and covered with fine white hairs. This plant prefers full sun and can handle dry to medium water conditions. If overwatered it has the tendency to flop. To prevent flopping cut the plant down to two or three feet in June. It will grow in most soil types but prefers well drained soil conditions.
Maximilian Sunflower grows from a rhizome. The rhizome is edible and it provided food similar to Jerusalem artichokes for the Native Americans. Maximilian Sunflower also attracts beneficial insects and birds. Maximilian Sunflower is used as an ingredient in range seeding mixtures to provide high quality forage for livestock. It also provides food and cover for wildlife. This sunflower is difficult for squirrels to climb so often birds get the seeds.
Helianthus maximiliani is a good perennial for the back of a border. It is a great addition to a garden because it is showy in the fall when most perennials are done flowering. Maximilian Sunflower is also great as a cut flower. You can find it at the Idaho Botanical Garden in the Herb Garden or near the Children’s Garden.
The genus Salvia is the largest in the botanical family, Lamiaceae (mint), with the number of species estimated to range from 800 to nearly 1,000. Salvias, commonly known as sage (not to be confused with the native Idaho sagebrush!), are easy to grow, usually right at home in sunny, well drained spots, and their toughness is matched only by their showiness. In addition, Salvia is an extremely important plant species for our pollinators. Bees, butterflies, and hummingbirds love the tubular or bell-shaped flowers, which come in a wide range of colors and are borne on tall spiky racemes held above the foliage.
No matter what your gardening style, there is a Salvia to suit your needs. The most common is probably Salvia officinalis, the culinary herb sage, found in most kitchen cupboards. Outside of the kitchen, this is an ornamental, evergreen perennial which would make an attractive addition to any herb garden or perennial bed. Culinary sage comes in variety of leaf colors: from the basic grey-green, to a variegated green-gold variety, to the very attractive cultivar ‘Purpurascens,’ with green leaves variegated with purple. Culinary sages flower in shades of blue.
You can find a number of Salvia species throughout the Idaho Botanical Garden. Visit the herb garden to find the culinary variety. Many of our containers features salvias, both annual and perennial. Look for Salvia guaranitica ‘Black & Blue’ paired with dark purple-leaved sweet potato vine in containers on the Plaza. ‘Black and Blue’ is an annual cultivar that features deep cobalt blue flowers with black calyces. Flowers appear on foot-long spikes over a long mid-summer to fall bloom.
Other mixed containers on the Plaza include Autumn sage, or Salvia greggii. This salvia is native to Texas and Mexico, where it is a reliable, drought-tolerant evergreen small shrub. Here in Idaho, treat it as an annual or tender perennial, requiring protection in winter. Some cold-hardy cultivars, such as ‘Furman’s Red’ and ‘Wild Thing,’ have proven to be perennial at the Denver Botanic Gardens and have been successful here in Boise. Salvia greggii is a valuable nectar source for hummingbirds and butterflies. Red is the most common flower color, but it’s also available in pale yellow, pink, fuchsia, and white.
You will find many more salvias in the areas of the garden that feature waterwise plants. The Plant Select beds include three outstanding Salvia species. Perennial Salvia darcyi (Mexican sage) ‘Vermilion Bluffs’ grows to be an impressive shrub, about 3 feet tall and wide. It blooms throughout the summer with bold crimson red flowers and truly deserves the often used title of “hummingbird magnet.” Also in the Plant Select beds, Salvia argentea, or Silver sage, is a spectacular foliage plant, with large felt-like leaves and white flowers on dramatic candelabra-like stems. Beetles can often be found pollinating Salvia argentea, as they are typically attracted to white flowers. A third salvia, Salvia pachyphylla, is known by many common names, including blue sage, rose sage, and Mojave sage. It has beautiful, aromatic silver foliage, topped with densely whorled bracts of purple surrounding delicate violet flowers. Salvia pachyphylla flowers from summer through fall and is extremely popular with native bumblebees, but also attracts butterflies and hummingbirds. Salvia pachyphylla is also on view in the BLM Firewise Garden.
Salvia dorrii, or Desert purple sage, is the classic “purple sage” of the western United States. You can find this salvia in the Lewis & Clark Native Plant Garden. Desert purple sage has aromatic silvery foliage and showy spikes of purple and blue flowers. It is a small, woody shrub, to about 18 inches, that blooms in late spring. Salvia dorrii is an especially valuable plant for native bees.
Salvia nemorosa ‘Caradonna’ is planted in the Water Conservation Landscape, located outside the Garden’s gates along Old Penitentiary Road. This extremely showy salvia, with flowers of vivid blue held on dark purple-black stems, is popular with both butterflies and hummingbirds. Drought and heat tolerant once established, Salvia nemorosa is an early summer bloomer and is suitable for planting in beds or containers.
This is just a small sampling of the various members of the genus Salvia. They are versatile and colorful, and many are drought tolerant and low maintenance. In addition to these qualities, Salvias will attract a wide range of pollinators to your garden. What’s not to love about these remarkable plants?
Nepeta x faassenii
With its gorgeous, long lasting blooms, lovely scent, and pollinator attracting power, Nepeta x faassenii is one of the great hybrid successes of the horticulture world. Read the article »
Bourbon, Hybrid Perpetual, Rambler, Modern Climbing, and Miniature Roses
The Bourbon rose originated from a natural cross between a China rose and a Damask rose on the island of Reunion in the Indian Ocean. The seeds to this rose showed up in Paris in 1891, and cuttings showed up not long after in 1821. The Bourbon rose has a re-blooming trait from the China rose and a strong fragrance because of the Damask rose. Thanks to these characteristics a whole new class of roses was born when the Bourbon rose was introduced. Read the article »
Centifolia, Moss, and China Roses
Historians believe that the Centifolia rose or the Cabbage rose is one of the oldest cultivated roses. It is believed to be a cross between Autumn Damask and an Alba Rose. Read the article »
Gallica and Damask Roses
The Gallica rose is one of the earliest cultivated species of roses. This rose was cultivated by the Greeks and the Romans and was commonly used in medieval gardens. It is native to central and southern Europe including France. It is a compact rose lacking a strong fragrance. The Gallica rose blossom ranges in color from rich pinks to purples. Read the article »
An Introduction to Old Garden Roses
There are many types of roses in the world of plants. Wild roses, which are truly wild roses, are not usually cultivated. Old garden roses are roses of horticultural origin that were established before 1867, when ‘La France’, the first of the hybrid tea roses, was introduced. Modern Garden Roses are the predominant roses of today. Modern roses are in active development today by hybridists unlike a lot of the old garden roses. Here at the Idaho Botanical Garden in the Jane Falk Oppenheimer Heirloom Rose Garden we feature roses bred and introduced before 1920. Read the article »