Sunday, July 17, 2011

Save Some Room for Summer Blooms

I like to point out to people that summer-blooming shrubs are attractive additions to the garden.  They provide fragrant and colorful blooms that we can use to add interest and beauty once the flush of spring blooms are gone.  These shrubs usually start blooming in May.  With careful planning you can have blooming shrubs into early August in North Georgia.

Hypericum frondosum 'Sunburst'

By the official date of summer, temperatures are often in the 80’s and this year we were in the 90’s in early June.  Therefore, I like to consider “summer shrubs” to be those that start in May.  At that point, the explosion of spring is complete, and we are seeing the second group of shrubs begin to flower.

Itea virginica

Virginia sweetspire (Itea virginica) is what I consider to be the first summer blooming shrub.  According to my records, flower buds were noticeably elongated and swollen by May 1st this year.  From a distance, that stage is pretty enough to given the appearance of blooms.  By May 21st, the blooms were fully open.  I saw one planting by the Alpharetta library that was so covered in blooms that at first I did not realize what it was!  This shrub is tolerant of wet areas but also does well in average garden conditions.  It loves morning sun but appreciates afternoon shade.  The fall color can be spectacular.

Hydrangea quercifolia

Native hydrangeas are a favorite of mine (and a favorite with the local deer); there are several species to consider for your garden. Oakleaf hydrangea (Hydrangea quercifolia) has beautiful oak leaf-shaped foliage and showy flower panicles. The flowers open around mid-May and are usually a mixture of demure fertile flowers and showy sterile ones.  But this species has a special trait: by late June the showy white petals have aged to rose pink.  These dried blooms remain on the plant for many months; the effect is such that it looks like it is still blooming!  Dwarf forms like ‘Pee Wee’ and double forms like ‘Snowflake’ afford the gardener some flexibility in using this beautiful southeastern native.

Hydrangea arborescens

Smooth hydrangea (Hydrangea arborescens) is best known in the gardening world for her cultivars: ‘Annabelle’ has delighted gardeners for years with showy white clusters while ‘Invincibelle Spirit’ and ‘Bella Anna’ are captivating folks anew with their pink flowers.  Of course I find the modest blooms of the species to be every bit as charming.  I have also recently purchased silverleaf hydrangea (Hydrangea radiata) which was previously considered a subspecies of H. arborescens.  Buds form on these hydrangeas in May, starting as bright green clusters; by early June the flowers start to open and continue to open for several weeks.  I spray my hydrangeas occasionally with Liquid Fence to deter the deer.

Bottlebrush buckeye is a plant that I try to convince more folks to consider.  Aesculus parviflora blooms much later than it’s cousin Red Buckeye (Aesculus pavia) plus it likes full sun, will get big if you give it room, and is popular with a whole different set of pollinators!  The first flowers open by early June and the flower spike fills out as blooms open from bottom to top.  Flowering continues into July as different spikes continue to bloom at their own pace.  Again, for those of you with large sunny spaces, this is a great plant to have.

New Jersey Tea (Ceanothus americanus) is a modest little shrub that most folks would mistake for a perennial.  Small clusters of tiny white flowers open in late May.  In the wild it often grows on woodland edges.  Give it more sun in the garden and it will grow into a handsome clump. It is the host plant for the Spring Azure and Summer Azure butterflies.

Elderberry (Sambucus) is a rowdy, rambunctious plant that loves wet roadsides.  I love to drive along country roads and see the dinner-plate sized flower clusters.  Each cluster is composed of dozens of creamy white flowers and the insects adore them.  If I pass that way again in a few months, those flowers have become plump purple berries – a feast for the birds.  My local Elderberry is now classified as Sambucus nigra ssp. canadensis.  Further north of us is Red Elderberry, Sambucus racemosa.  If you’ve got room for this shrub, local wildlife will love you for it.

Rhododendron x 'Millenium'

Some species of native azaleas bloom into early and mid-summer in my garden.  With careful selection, you can have blooming azaleas even in August in North Georgia. Rhododendron viscosum (Swamp azalea) was in full bloom on 5/30 along with R. arborescens.  The ‘Millenium’ hybrid, which has mixed parentage but certainly has some R. viscosum (for fragrance) and R. prunifolium (for color), started blooming several weeks later, and the species R. prunifolium is blooming right now in mid-July.  Each blooms for about 3 weeks.

Hypericum densiflorum

Shrubs in the genus Hypericum are commonly known as St. John’s Wort.  There are several species that grow well in my area.  They are outstanding shrubs for sun, can handle drier conditions and some of them can even handle wet areas. In general, the blue-green foliage of Hypericum is very attractive.

In my yard is a small species that is almost a ground cover.  I think it is St. Andrew’s Cross, Hypericum hypericoides.  The quiet little bloom is in sharp contrast to the showier St. John’s wort cultivars like Hypericum frondosum ‘Creel’s Gold’ and 'Sunburst'. A friend gave me a young Hypericum densiflorum plant.  The pleated, dark green foliage is a nice foil to the flowers.  I also have a young plant that is currently growing in standing water (in a wheelbarrow full of tadpoles!).  I didn’t mean for it to do that but I got busy and it rained a lot in the spring ….

Clethra alnifolia

Clethra is probably the latest shrub to bloom in my yard. The white dwarf cultivar Clethra alnifolia 'Hummingbird' starts to bloom in very late June, while the species (the pink Clethra alnifolia) may not start until mid-July.  Once the blooms open, insects are doing the happy dance on those flower clusters from morning until dark!

So if you're looking to add some plants to your garden, give summer shrubs a look and you'll have more flowers throughout the year.


  1. I was just watching the bumble bees this morning fighting their way through the Hypericum anthers. We have an herbaceous species in the midwest that is very similar to your southern beauties - Hypericum pyramidatum.

  2. Thanks for mentioning that, Heather. It is true that even we have some Hypericum species that are herbaceous (some even considered as Annual, I see). I have a tiny little one that I need to finish identifying, I think it might be Hypericum mutilum. What a great group of plants.