Expert: The Long Island Gardener - 8/7/2008

Question
I HAVE A CREPE MYRTLE IN MY YARD AND IT'S KIND OF SHADED SLIGHTLY BY A RED OAK TREE. I THINK IT'S PROBABLY AROUND 5 FOOT TALL. I WISH TO GIVE IT MORE OF A CHANCE TO LIVE AND GROW. WHAT SHOULD I DO FOR IT? WHAT KIND OF FERTILIZER SHOULD IT HAVE?
I ALSO HAVE A COUPLE OF BLUEBERRIES AND A RASPBERRY PLANT. WHAT KINDS OF FERTILIZER SHOULD THEY HAVE? AND DO BLUEBERRIES DO BETTER IN FULL SUN OR PART SHADE? I THOUGHT THAT I MIGHT PUT PINE NEEDLES AROUND THEM,TO MULCH THEM AGAINST WEEDS AND CRABGRASS. THANKS MUCH!
                               ANNETTE FORBES

Answer
Fertilizer will NOT compensate for lack of Sun, my friend.

People tend to forget that Plants are AUTO-TROPHS.  They make their own food.  They do that with Sunlight.  The minerals they use help them build Chloroplasts, make seeds, and do other growth related things.

If you want to make your Myrtle happy, give it SUPERSOIL.  And try thinning out the branches of your Oak to increase the amount of light it gets.  I can't stress this enough: Increasing the amount of available LIGHT is the most important thing you can do for this plant.

To rev up your Soil, top dress it with Organic Matter: Humus, aged Manure, aged Compost.  Fertilizes are SALTS by definition and will not do anything special for your Myrtle.  Especially if your Soil is good.  Because it's got everything it needs.  (Except Sun.)

Your other plants are also Full Sun shrubs.  How do the leaves look?  Any symptoms of Chlorosis?  They need REALLY Acidic Soil conditions or they can't function.

The National Sustainable Agriculture Information Service posts a page on growing Blueberries at their website:

attra.ncat.org/attra-pub/blueberry.html

'When Soil pH is appreciably higher than 5.5, Iron Chlorosis often results; when Soil pH drops below 4.8, the possibility of Manganese toxicity arises.  In either case, plants do not perform well.'

They declare Sulphur to be the preferred method of acidifying Soil.  Like the Lime used for reaching a Grass-friendly pH, Sulphur takes a year or longer to alter Soil chemistry.  However, Sulphur is a bit harsh on Soil; it's a chemical, and it takes a toll on the microbes population.  Try Peat Moss instead; it has the low pH you want.

Although Blueberries have low Nitrogen needs, they demand their N in the form of Ammonium, not Nitrate-form Nitrogen.  Fertilizing with Fish Emulsion allows available N to be efficiently turned into stable Ammonium and released slowly.  Pine Needles are a good mulch in this case, but they decompose too slowly to be of immediate value.  They are great as you point out for controlling Weeds.

THE LONG ISLAND GARDENER