Friday, April 26, 2013

An Amazing Spring For Magnolias In New England

The purple Saucer Magnolia - 2013 BDG

I still don't feel like posting my piece on mulch in the wake of the past two weeks here, so I will focus on some of the beautiful revelations this week as our spring continues its slow and consistent march forward.  One of the great beneficiaries to a "Goldilocks Spring"(not too hot and not too cold), is the Magnolia.

Here in New England if we get a week of warm weather they open and drop their petals very quickly.  On the other hand, if they open and we get a  frost, the petals burn(turn brown) and drop.

Star Magnolia finishing its three week bloom - 2013 BDG

The most susceptible seems to be the Star Magnolia (Magnolia stellata), rarely do we get a show like we have had this year with them blooming for three weeks.  They are called Star Magnolia for the star shaped flowers with many petals.  The Star Magnolia seems to open a week or two before the Saucer Magnolia (Magnolia soulangiana).  The Saucer Magnolias are having an amazing spring too with many different cultivars their colors ranging from the purples to roses and to pale pinks.

A rose Saucer Magnolia - 2013 BDG

I don't typically use Magnolias in my designs in New England because space is at a premium on most of the properties I work, and I often choose ornamental trees that offer more throughout the seasons, but on these spring days, it makes me want to re-think my opinion.  Also, I don't want to get the Magnolia Society upset at me.

There are many other species: kobus, lilliflora, denudata, acuminata, virginiana and crosses of these species that are available at some nurseries in the area.  I know a few people that even have the classic evergreen southern Magnolia growing on their properties, but that is an iffy proposition around here.  The virginiana or Sweet Bay Magnolia is another favorite that flowers a little later and can be quite fragrant, but the flower display is not on the level of these early spring Magnolias.  There are some reliable yellow flowering Magnolias that are crosses between denudata and the cucumber Magnolia (acuminata).  "Butterflies" and "Elizabeth" are two commonly available yellow-flowering plants.  

Acer japonica "Aconitifolium" - 2013 BDG
Speaking of other ornamental trees that work hard all year long, I have included some images of my favorite Stewartia pseudocamellia breaking bud and another favorite Acer japonica "Aconitifolium".  These are two of my favorite trees for highest visibility areas year round.  The red flower and emerging leaves on the Japanese Maple are stunning in the spring, while the lime-green color of the Stewartia leaves are so distinctive in color and form.

Stewartia pseudocamellia just leafing out - 2013 BDG
Pulmonaria, the first perennial to bloom with the bulbs - 2013 BDG

Friday, April 19, 2013

Spring, And Life, Goes On In Boston.

Young boy having a swing at Wright-Locke Farm
This morning as I finished my weekly posting, I realized how unimportant my words on mulch and organic amendments  would be this week, but, like most Bostonians, I was not going to stop or alter my work because of a few misguided and soulless individuals. 

On Tuesday, my wife was on the MIT campus interviewing for a job and we live only a few towns over from Watertown, but we will not live in fear of these cowards while we grieve for those affected by this tragedy.  

Dennis Lehane, the well-known author and an authentic voice for this city wrote a poignant Op-Ed in the New York Times:  Messing with the Wrong City.  Lehane and others were on NPR this week and the following links to the program:  Lehane interview on NPR

Instead, I want to focus on the beautiful spring that is unfurling this week.  Just yesterday I was at a children's vacation camp at Wright-Locke Farm, to write a story and take photos for our local paper.  These young children spent a week on the farm doing chores, exploring and enjoying time on our beautiful suburban working farm.  The photo above is of a young boy on a swing that hangs from the rafters of the nearly 200 year old barn.  Despite all that is going on, the innocence of our children is intact.

This morning I visited a neighbor who has a stunning and ancient Weeping Cherry Tree in his front yard.  For years I have marveled at its size and grace.  It has been through a lot in recent years with the Winter Moth and drought.  In talking with the neighbor, he revealed it was knocked over during a hurricane in the '50s, but the neighbors came out and pushed it back up in place.  It stands 50 feet tall and maybe 70 feet wide and has endured insects, disease and many storms.  I love how this represents the character of Bostonians this week.

God has given us one of the most beautiful spring weeks and I choose to be grateful for this and not to give in to anger and fear.

Friday, April 12, 2013

Downy Mildew, Why Not To Buy Impatiens This Year!

Hanging Baskets of the susceptible Impatiens walleriana ©2013 BDG
I love Impatiens for what they do in the garden.  In part to deep shade they softly fill holes in beds with color that lasts from June to first frost.  Nowadays they come in single and double flowers and just about any color and, best of all, they are cheap.  But, the Impatiens(specifically Impatiens walleriana the common bedding plant) is under attack from a devastating disease that turns the leaves yellow and ultimately strips the plant of its leaves and flowers until it is dead.  I had many clients and friends lose Impatiens last year through no fault of their own.  

I apologize for the marginal photos as they were taken with my phone at the growing facility.

Downy Mildew, a real problem for your Impatiens

4" Pot of walleriana  ©2013 BDG
Last September I wrote a piece on Downy Mildew, A Real Downer and how it had eliminated many Impatiens plantings in the area, both in the ground and in containers.  Downy Mildew is a fungal disease that has proven lethal to certain common Impatiens in the Eastern US through the midwest and down to Florida, and unfortunately there is nothing the homeowner can do about it.  Propagators and growers are completely drenching their plants in chemicals on a weekly basis just to get them to market free of infection.  Check out the following link from Sygenta on proposed preventative protocols for growing Impatiens. 

You don't even want to know about some of those products used.  All of this work and chemical application for a plant that could still die several weeks after you bring it home and it is exposed to the spores in your garden.  This can happen because the spores remain in the ground overwinter and when disturbed by splashing water, wind or shovels they can travel on the wind for miles.

Following is a very informative sheet from Ball Horticulture, one of the big guys in the plant world, on guidelines for growers: Impatiens Downy Mildew:  Guidelines for Growers.

What will happen this season

New Guinea Impatiens ©2013 BDG
I spoke with the Greenhouse Manager, Reda Barsoun, at Mahoney's, a local nursery that has a significant annual growing operation in the Boston area.  He said this year they have cut in half their growing of Impatiens walleriana and that most of them will be in hanging baskets.  Reda and his growing manager, Bobby, feel that hanging baskets have less of a chance of being infected than plants in the ground.

New Guinea Impatiens ©2013 BDG
At the nursery they will have postings warning people about Downy Mildew and offering suggestions for plants to use in their place.  I think this is responsible, since they will also mention on the post that they will not offer refunds on Impatiens.  Check out the following article in Greenhouse Grower on what the industry is doing: Greenhouse Grower article on Downy Mildew

While production of the walleriana species is cut, Mahoney's has doubled their growing of Impatiens hawkeri, or New Guinea Impatiens.  And this year, nurseries will have a relatively new Impatiens called SunPatiens, a new plant hybrid from Sakata Ornamental.  Both of these plants are not susceptible to Downy Mildew.

Range of Red New Guineas  ©2013 BDG
Most of us know the New Guinea Impatiens which does great in the sun.  It is a much bigger plant with larger and more coarse leaves and a range of flower colors that can be a little harsh, not the softer pastels you could find with the walleriana species.  The New Guinea and SunPatiens do great in the sun and part shade, but they just can't substitute for the old-fashioned walleriana species in the shade.  Reda says that the Sunpatiens tend to be more spreading than upright like the New Guinea and their flower size is in between the New Guinea and walleriana.  There will be a broad range of color choices, but you won't find some of the more subtle colors.  They will grow in deep shade but their flower production will be very light.

What to do...

Hanging New Guineas ©2013 BDG
I am not going to buy any Impatiens walleriana this year for myself or clients.  If you want to try you can buy them in hanging baskets or put them in containers, but I feel there is a good chance they will not make it through the summer.  If you plant in the ground, especially where you may have had impatiens last year that died, they will almost certainly die and quickly.  In a part shade area I am going to try some of the SunPatiens, there is a nice pale pink variety that I will let spread in an area that could use some color.

Pink SunPatiens just potted
©2013 BDG
In the deeper shade where I have some planned holes in my gardens I will plant Torenia.  I have always loved Torenia in shade containers as they are excellent at trailing and they have a good range of colors. I think this may be one of the best substitutes in the shade.

White SunPatiens just potted
©2013 BDG
Another idea in shade is Begonia.  Now, I can hear the collective groans of people who hate Begonias, but maybe you haven't seen some of the dazzling Begonias available.  So often we think of the little, waxy leafed plants with tiny flowers we see in the nursery or on our grandmother's windowsill.  There are some beautiful big flowered begonias with some amazing flower colors like the "Dragon Wing" series or tuberous Begonias.

Violet Torenia @ Proven Winners
There are some fantastic Coleus that have wonderful foliage color to add contrast and color in the shade.

Check out my blog post from last fall for some other ideas.

Pink Dragon Wing Begonia
@ Proven Winners
We may end up seeing Impatiens walleriana disappear for a few years and I am sure that some scientist will come up with a new variation that is resistant to the disease.  I hope so, because I will definitely miss this plant in my deep shade garden.

Spring is progressing -- Pushkinia, Scilla, Crocus and Daffodil
with Muscari coming in next couple of weeks.  ©2013 BDG

Friday, April 5, 2013

Growing Degree Days Explain Why This Spring Seems Late...But Is It Late?

Snow Drops finishing with Rock Iris going strong. Daffodils and Squill
starting to come.   2013©BDG
Do you remember last came all at once in a massive explosion of color, leaves and pollen.  Snowdrops, Squill and Daffodils all came at the same time, while Maples flowered and dispersed their pollen.  During the last week of March in 2012, Forsythia, PJM Rhododendrons and Star Magnolias were already in full bloom and my tree lilacs, an early tree to leaf out, were already in leaf.  However, this year you have to search hard to find any buds swelling and only this week did Squill start to appear and Daffodils start showing flower buds.

Squill (Scilla siberica) loving the sun.  2013©BDG
Why the dramatic difference from one year to the next?  The answer comes in three words-- Growing Degree Days(GDD).  By tracking this measurement you can tell when plants will flower and when the bugs will hatch.  While the calendar is a good guide for Baseball's Opening Day, there can be quite a variation when it comes to plants and insects, since they go on their own calendar that is based upon weather and temperature.

One GDD is equal to the number of degrees the average daily temperature is above 50 degrees.  You take the average of the high and low for the day and subtract 50.

Serviceberry (Amelanchier canadensis) flower buds
emerging, should flower at 75GDD.  2013©BDG
(High Temperature + Low Temperature) / 2 - 50 = GDD

You can do it yourself or rely upon your local State School Extension.  I use UMass -- click on the Landscape Message tab for timely updates.

This season we haven't had many warm days and the evenings have remained very cold, so as of today, April 5th we have had a paltry 1.5 GDD for the season.  Last year we had 103 GDD by the end of March.  These numbers seem small since last year we accumulated nearly 3,300 GDD, but a lot of activity happens in these first couple hundred GDD.  Late in the summer with 90+ degree days and warm nights we can add 300 GDD in a week, while in some years we may only accumulate a total of 300 GDD by the end of May. 

So, is spring late this year or were we early last year?  I pulled some annual information from UMass and looked at GDD and soil temperature for the last 10 years.

Saucer Magnolia (Magnolia soulangiana) swelling slightly
but holding tight.  Should flower at 50-75 GDD.  2013©BDG
Year     GDD     Soil Temp
2013     1.5         48
2012     103        49
2011     12          42
2010     20          44
2009     3            49
2008     19          36
2007     35          35
2006     17          39
2005     0            32
2004     17          37

Andromeda (Pieris japonica) just opening some flowers.
Should flower around 50 GDD 2013 ©BDG
The data reveals that we might be a little late this year when compared to the past decade, but  last year was most definitely early.  With all the late snow we had this year maybe we are just hoping for spring to come.  By this time last year we had already had three good weeks of spring.  I remember that I had mostly cleaned up and prepped my gardens by the end of March.  That is certainly not the case this year as I still have a chunk of snow in my back yard.

One of the nice things about spring coming slowly is that the flowers are nicely spaced out and last longer in the cool weather.  The later that Magnolia's flower gives them a better chance of lasting, as they get easily burned with frost.

The dreaded Winter Moth that is devastating many of our shade and ornamental trees emerges within the first 50 GDD, and last year the arborists had already sprayed once for the moth and this year they are just waiting for the plant and insect world to waken from its slumber.

My lovely Witch Hazel entering its third month of
flowering, but I know its days are numbered.  2013©BDG
During the first 50 GDD you can expect to see PJM Rhododendrons, Forsythia, Star Magnolia and Pieris starting to flower.  It is also the time that the Witch Hazels finish and drop their flowers.  My Witch Hazel is still in bloom, lasting more than two months and without the heat the flowers have stayed fresh, and will be around at least for another week or two.

At 100 GDD you start to see the native Dogwood (Cornus florida) and Crabapple flowers.  Check out this Cornell IPM Fact Sheet on flowing times for plants.

No matter how much you analyze, hope or pray, spring will come when it comes and there is nothing I can do about it.