There is a Cure for the Summertime Blues

Like some television commercials say about their product, “But wait, there’s more”, this statement can also be said about flowering shrubs. Just because spring is over, it does not mean there is no more color in the garden. Yes, there are herbaceous perennials that bloom in summer, but there are some fabulous flowering shrubs that also shine during the dog days of summer besides roses and Japanese spirea. Here are three of my favorite larger shrubs with big landscape impact.

Roses ('Graham Thomas') are not the only shrub that blooms in summer
Roses (‘Graham Thomas’) are not the only shrubs that blooms in summer

Bottlebrush buckeye (Aesculus parviflora) produces flowers in the northern U.S. in early July. The white flowers are especially unique and are borne on large, 8-12” long panicles rising far above the leaves. The flowers resemble a large bottlebrush and are often home to visiting butterflies and bees.

Bottlebrush-like flowers
Bottlebrush-like flowers
Bottlebrush buckeye in full bloom
Bottlebrush buckeye in full bloom

In autumn, the foliage turns bright yellow early in the season. This large, spreading, suckering shrub needs a lot of space to grow reaching 8-12′ tall and 12-15’ wide at maturity. It is native to the southeastern U.S. and performs best in rich, moist, well-drained soil, but is adaptable to most soils and pH. Bottlebrush buckeye grows in shade to partial shade and out of the hot afternoon sun. Unlike its tree relatives, this Aesculus species is not susceptible to powdery mildew, leaf blotch or leaf scorch and is hardy to zone 4b.

 ‘Nordine’ smokebush (Cotinus coggygria ‘Nordine’) is another large, wide-spreading, upright shrub that grows 10-15′ tall and wide. It produces purplish-red new leaves throughout the growing season that later turn dark bluish-green. When crushed, these leaves smell like a combination of radishes and oranges.

'Nordine' smokebush in full bloom
‘Nordine’ smokebush in full bloom

The individual flowers are not particularly attractive, however, that quickly changes. The hairs on the individual stems of the 6-8” long flower panicle elongate and turn a wonderful smoky pink to purple color that lasts for many months. The orange-yellow to purple fall color is equally appealing.

Hairy flower panicles of 'Nordine' smokebush
Hairy flower panicles of ‘Nordine’ smokebush

The species is native to southern Europe over to central China and the Himalayas. This particular cultivar of smokebush is hardier than other purple-leaved cultivars of smokebush and should reliably flower in zone 4b each year. It is able to withstand most soils and pH, full sun, drought, and urban conditions. Deer don’t seem to bother this plant. Maybe the smoky appearance of the flowers scares them away?

‘Limelight’ panicle hydrangea (Hydrangea paniculata ‘Limelight’) is one of the best flowering cultivars of panicle hydrangea. The flower panicles are huge, up to 6-10” long starting lime-green and eventually turning all white. As the flowers fade, they turn pinkish to brown from fall through winter providing multi-seasonal interest. The added benefit of this cultivar is that the flowers are borne on strong stems that are held upright, so flowers will not flop over like some other panicle hydrangea cultivars.

Green flowers of 'Limelight' hydrangea before they turn white
Green flowers of ‘Limelight’ hydrangea before they turn white

‘Limelight’ hydrangea is smaller than the species growing 6-8’ tall and 5-6’ wide at maturity with an upright, spreading form. The species is native to Japan and China and hardy to zone 4a. Panicle hydrangea does well in an organic, fertile soil, but is quite adaptable to soil and pH. It requires full sun for the best flower display and moist, well-drained soil, but it is not as finicky about soil moisture as some of the other species of Hydrangea.

'Limelight' panicle hydrangea in full bloom
‘Limelight’ panicle hydrangea in full bloom

When designing a landscape, incorporate a variety of trees, shrubs and perennials to insure continual bloom throughout most of the growing season. These three, non-invasive shrubs are all available at most nurseries and garden centers. If you have not tried one of these beauties yet, plant one or all three in your yard. You will be happy you did.

–Laura Jull, a.k.a. The Lorax

Go sport fishing at your local nursery

Regular fishing, for actual fish, is quite possibly the second most boring think ever invented (First place, of course, goes without question to baseball) but sport fishing! Now THAT is something I can get behind.

By sport fishing I mean, of course, looking for sports – chance mutations – in plants. Sometimes a flower color changes, or sometimes a leaf becomes variegated, like on this lilac branch I found at a friend’s nursery a couple years ago

variegatedsyringa

Nurseries are great places to go “fishing” for these sports, simply by walking down the rows of plants looking for anything odd or out of place. Sometimes they are true sports, and sometimes there has been some hanky panky… Last summer I was walking through a nursery looking at their pots of blooming Sweet William (Dianthus barbatus)

sweetwilliam

And suddenly I noticed a plant that was markedly different.dianthus hybrid

Way too different to just be a sport, this was a chance hybrid with… something. What, I don’t know, Dianthus is a big, promiscuous genus, but I like it and snatched it up. The chance hybrid was pretty enough and intriguing, and after blooming it produced a healthy crop of seeds, so I grew some out. One year later, they’re blooming in all sorts of interesting ways..

One looks just like a regular Sweet William, but significantly shorter

dianthusf22

Another is a nice red, though the flowers are a bit sparse

dianthusf23

And this one, my favorite, has decided to pretend to be a carnation with masses of double, fragrant flowers.

dianthusf21

I, of course, have responded by collecting many many more seeds from that original chance hybrid picked up at the nursery, and can’t wait to sow them out and see what else may show itself.

So next time you at a big nursery, take some time to go fishing for sports and hybrids… you may just find something cool.

— Joseph Tychonievich

Uncommon Clematis

– Holly Scoggins

Here’s a couple of clematis (clemati?) you may not be familiar with. Both are easy to grow but differ from the more common large-flowered form. There is a great deal of hybridization within the genus, so many cultivars are placed within “groups” rather than described as a cultivar of the species.

Clematis ‘Princess Diane’
Texensis GroupClematis 'Princess Diana' in the author's garden.

Clematis ‘Princess Diana’ in the author’s garden.

Crossing a large-flower clematis cultivar with Clematis texensis (scarlet leather flower) resulted in this lily-shaped beauty. Pointy little buds open as four hot pink tepals; bright yellow stamens grace the center. The buds on this rebloomer just keep coming; mine has been blooming for 40 days at this point and doesn’t seem to be slowing down. The princess seems pretty happy in her part-shade (sun in the afternoon) situation in my garden.I swear there's a lovely wire tuteur under there...

I swear there’s a lovely wire tuteur under there…

 

Some catalogs/sites describe ‘Princess Diana” as reaching only 8’ in length; mine’s wrapped up and down a 6’ tall tuteur/trellis thingy at least 4 times. Guess I need a bigger tuteur (doesn’t everybody?). Cold hardiness seems to be up for discussion – some sources state USDA Zones 6 to 9, others 4 to 8 (I’m a solid 6a here in the mountains of SW Virginia, recently warmed-up from 5b).

Various pruning strategies are associated with different groups of clematis. This one dies back to the ground and blooms on new wood, so I just cut it back in early spring to clean last year’s vines out of the wire supports.

Clematis xdiversifolia ‘Blue Boy’
Herbaceous/Integrifolia GroupClematis 'Blue Boy' scrambles through a deciduous azalea.

Clematis ‘Blue Boy’ scrambles through a deciduous azalea.

‘Blue Boy’ is one of the herbaceous clematis, resulting from a hybrid of Clematis integrifolia and C. viticella. Multiple stems arise from the crown and scramble, flop, and otherwise meander through and over anything in the vicinity. Lovely blue-violet blooms festoon the stems from early June through frost (“festoon” is one of my favorite words – need more opportunities to use it!)

Nice contrast to the ornate foliage of Ligularia japonica.

The rosy stems contrast nicely with the ornate foliage of Ligularia japonica.

Despite its delicate appearance, this is a very tough and cold-hardy (Zone 3!) clematis. Enjoy all summer, and then chop ‘Blue Boy’ back with the rest of your die-back perennials in winter.

Linked is a wonderful, detailed piece by Julie Lane-Gay on the herbaceous clematis group:
http://www.pacifichorticulture.org/articles/better-in-relationship-herbaceous-clematis/

 

Welcome to our new home!

This month, the Garden Professors have moved to a new website. You can still easily find us at gardenprofessors.com (bookmark that address!), but we’re no longer actively posting on the eXtension website. This change was necessitated by eXtension’s decision to restrict leadership to faculty belonging to premium universities (those paying a sizable annual membership fee). Since neither Dr. Gillman nor Dr. Chalker-Scott belongs to a premium university, and since both are founding members of the Garden Professors, we made a group decision to host our blog independently.

We’ve been working on this transition for a number of months, which is partially why we haven’t been posting as often as we’d like. Along with our new space we’ve added some new members: Dr. Laura Jull (University of Wisconsin), Joseph Tychonievich, and Raymond Eckhart will be joining us as regular bloggers. We’ll be adding blurbs on each of these new members in our “Who We Are” section.

Ideally we’ll be posting on a daily basis, meaning more consistent posts for you. We’ll also be including posts from guest bloggers (our “visiting professors”). And you can also visit us on Facebook, where we have both a page and a group. The group is a great place for you to ask questions or start discussions on topics that aren’t in our archives.

We look forward to bringing you more good science-based gardening information in our own unique ways. Thanks for sticking with us!

IMG_7778The original Fab Four