Friday, August 30, 2013

Evidence Of Drought Stress Is Everywhere Around Boston

Dogwood with classic drought stress symptoms with
crispy tips and edges to leaves.  ©2013BDG
We have have had an interesting summer in New England as far as rain and temperature goes, but it seems as though every year is interesting -- just in different ways.

The predominant issue coming into the fall is that we are low on precipitation, and it is worse than the numbers reveal because most of our rain has come in quick dumps or large sustained events.  

According to the Blue Hill Observatory, just south of Boston, we are 1" below the 30 year average for August, and all but a trace of this month's rain came in a storm in early August that dumped over 2" in a few hours.  These quick and hard rains almost never infiltrate to the plant roots as it tends to runoff faster than the soil can absorb it.  July was also below the 30 year average for rainfall. So, for the last two months our gardens have not been getting the water they need.

I am not making a political statement but it is hard to
dispute that man and the industrial age has had an
effect upon our climate.  ©Blue Hill Observatory
June was a statistical aberration coming in 8" above the 30 year average, yet over 10" of the 12" that fell in June came between June 9th and June 19th.  Then, as we all remember, came the brutal two week heat wave that stressed everything.  We had the 4th wettest June on record followed by the 3rd hottest July on record, and now that August is finishing we will have a warm weather month where the average temperature is below the 30 year average for the first time in the past three years.

So what does this all mean in the garden.  

Japanese Maple with crispy tips.  ©2013BDG
It means that our bigger plants and trees, that don't benefit from irrigation, are thirsty.  Many of the images here show plants with varying degrees of stress.  Burn't leaf edges, early leaf drop, contorted or sagging leaves are some of the clues.  Evergreen plants and trees do not show their stress until it is too late, so make sure you water them as well.

Irrigation systems are great for lawns, perennials and small shrubs.  They are designed to deliver water for plants and lawn that live in the top foot of the soil.  Our bigger plants and trees require water deeper in the soil and when it doesn't get replenished by deep soaking rains they suffer and it often doesn't show until subsequent seasons in large trees.  The only downfall to irrigation systems is that people can lose touch with their gardens.  Sure you don't have to go out and move the sprinkler every couple of hours, but with a system, people often assume everything is OK.

Birches are plants from the riparian
zone and need lots of water.  They
are often the first to show drought
stress.  ©2013BDG
I have been out in my garden over the past weeks and I am telling clients and friends to put a hose at the base of their ornamental trees and bigger plants and let water trickle into the root zone for a few hours(depending upon the size of the plant).  Turn the hose on so it flows well, but not very strongly, and place it a foot or two away from the trunk of your shrub or tree.  Let the water flow for an hour or two.   A big (15-20') Dogwood or Japanese Maple would love 2-3 hours and move the hose around once or twice during the time so a broad area of the root zone gets moisture.  Younger and smaller plants only need an hour or so to replenish moisture in the root zone.  Set a kitchen timer to remind yourself to move the hose.

So what plants really need watering.  All of your ornamental trees (evergreen and deciduous) will benefit as well as any tree that was planted less than five years ago.  Large shrubs that may get limited or no irrigation like Lilacs, Viburnum or Holly as examples.

Leaf litter is a sure sign that something is stressed.  Look
up to find out what is happening.  ©2013BDG
Standing with a hose and watering for a minute or two will cause more harm than good as it will force the roots to grow close to the surface for water making them worse off during times of drought.  A great rule of thumb for all watering (including the lawn) is to water deeply and less often.  If your irrigation system comes on every day you should talk to someone knowledgeable about adjusting it (and saving money).

A lot of people talk about using native plants in gardens as they are better adapted to our local temperature and precipitation patterns, among many other good reasons, but when you have significant variations in weather, even natives are not immune to drought.  A plant that is native in New England still needs an inch of water a week to be happy.

Lawn without irrigation is not doing well.  It has gone
dormant and will come back in the fall, but some water
will make sure it doesn't die.  ©2013 BDG
So get out there and give your ornamentals a drink.  Don't let them go into the fall and winter stressed from lack of moisture or they will not perform well or die in subsequent years.  One good soak over the next week or two will set them up well for the fall provided we get back on track with rainfall.

Rhododendrons are shallow-rooted and stress easily.
This will look great two hours after being
watered. ©2013 BDG

Thursday, August 22, 2013

"Plants In Containers Do Not Properly Represent Their Mature Size!"

Do you remember the phrase on your side view mirrors:  "Objects in mirror are closer than they appear?"

Bruce MacDowell, owner of Stonegate does amazing
stonework, and this is an example at the nursery
 with a weeping Hemlock and Japanese Maple by
a waterfall.  ©2013 BDG
Well, with plants it would be appropriate to say, "plants in your garden will be larger than the plant tag or nursery promised." How often have you bought a cute little specimen evergreen to find it overwhelming the space in several years.  Those wonderful 2' Weeping Japanese Maples want to be big broad beasts over time and their beauty only increases with their size, but if you want to place it on the edge of your front walk or driveway, be prepared to move it in short order.

Tags on plants in retail nurseries are great guides, but often the sizes they are referring to are sizes in five or ten years.  Recently I heard a story where a contractor told a customer she would love the plant he was installing in five years, but what he didn't tell her was that she would hate it in ten years as the plant would outgrow the space requiring constant pruning and decreased flowering.

A 5' specimen of a "Nana Gracilis'
 dwarf Hinoki Cypress.  Very old, very
expensive and a big old root
ball. ©2013 BDG
Maybe I wasn't paying attention before, but it seems as though the new marketing trend on tags is to provide a plant size in five to ten years.  Well that's great, but how about twenty or thirty years.  Do growers expect people will tire of their plants and change them out in ten years... maybe they're right.  I know that I am always looking to add new plants and try out cool new introductions.

When designing with plants, especially on foundations or in tight places, I always spend the effort to try and choose the right plant.  One of the best resources for understanding plants and their true sizes is the Manual of Woody Landscape Plants, by Michael Dirr.  When you spend the effort to specify and plant the right plant for a given location, less work is needed to keep it and other plants to their design intent.

A favorite nursery of mine in Lincoln, Stonegate Gardens Nursery, has  excellent large specimens of so many plants.  Often people don't get a chance to see some of these plants in their glory, let alone be able to purchase and plant them.  The images are of a few interesting finds last we during a visit.

Pinus parviflora 'Bergmanii' - A dwarf Japanese White Pine with
multiple leaders and a broad, open form.  This one is 6' tall and wide.
Wonderful specimen with some space.  ©2013 BDG
Tsuga canadensis 'Pendula' - Weeping Hemlock.  This beautiful specimen
is 5' tall and wide.  It can be pruned to accentuate the layered
branching.  Great by a terrace or over a wall.
Cercidiphyllum japonicum 'Pendula' - Weeping Katsura.  This slow
grower is already 8-10' tall and wide and will double in size.
Katsura's heart shaped leaves go through many color changes
and have a great apricot fall color.  ©2013 BDG
Seven Son Flower- Heptacodium miconoides
I have never liked this plant as it can have
such an awkward form, but this beautiful
10' specimen may just change my mind.
Great late summer/fall flowers and cool seed
heads.  ©2013 BDG

Friday, August 2, 2013

Images From The "Dog Days of Summer".

A riot of Echinacea live for the "Dog Days"  ©2013 BDG
Having survived the brutal July heatwave, we are now experiencing some atypically mild temperatures for the "Dog Days of Summer".  With the memory of the heat lingering, I can still see a client's newly installed plants wilting under the oppressive heat and lack of rain. But we have been given a reprieve and the "Dog Days" are, for the moment, not bearing their teeth.

Where did the phrase "Dog Days of Summer" originate?  I ask this question as it has been driven into my mind by a mad spin instructor who likes to play a song by Florence and the Machine, "Dog Days are Over".  Who knows what the song means, but it seems as though life is heading downhill in the song.  Me, I can't wait for them to be over as I love the weather in September, but I am enjoying these few nice 80-85 degree days.

Verbena never wilts under the heat  ©2013 BDG
Loosely translated, the "Dog Days" are from mid-July to mid-August and, for most of us in New England, these are the hottest and most stifling days of the summer -- days best spent on the beaches of the Cape and Islands or on a lake up north.  The phrase comes from many ancient cultures (Egyptians, Greeks, Romans and others) who noted the time of year when one of the brightest stars in the sky, Sirius, rose with the sun in the morning.  Romans believed that this bright star combined its heat with the sun and made these days unbearably hot.  Sirius for thousands of years has been known as the Dog Star as it is the leading star in the constellation of Canis major, which is one of Orion's hunting dogs.  So during the year when Sirius rises in the morning, it is considered to be the "Dog Days of Summer."  In the interest of disclosure, I gathered this information from a few astronomy sites and the previous link.

With that, following are some images from my garden during these "Dog Days".

Nicotiana (Flowering Tobacco) standing tall  ©2013 BDG
Zinnia that is still mad that I missed watering a few days
during the heat ©2013 BDG
Classic Verberna bonariensis just
starting to flower ©2013 BDG
Clethra alternifolia's fragrance in the
late summer evenings ©2013 BDG

Clethra barbinervis flowering in the dappled sun ©2013 BDG
Geranium 'Rozanne' will flower til frost ©2013 BDG
Love this neon red/orange Geranium against the
 chartreuse foliage ©2013 BDG
More Echinacea thriving in the heat ©2013 BDG
Not a flower, but bright colors for the
shady entrance ©2013 BDG
"Sun Power" Hosta adds great contrast color
in a sunny spot ©2013 BDG
Angelonia always reliable in the sun ©2013 BDG
"Bright Eyes" Phlox ©2013 BDG
Bee Balm (Monarda) finishing in front of the Echinacea ©2013 BDG