What Is Bark?

Garden Caregarden TriviaPlant Health CareUncategorized
Written By Peter Morris

Introduction

 Bark is the outermost layer of tissue on a mature plant. It is made mostly of dead rectangular cork cells that fit tightly together.  It is pretty much watertight!The bark on trees and shrubs is as distinctive and individual as the species that produce them.  Not surprising, there is a large variation in bark color, shapes and texture.  Aside from a broad range in visual characteristics – some features are clearly coming from a disease or disorder. Let’s see some examples ! 

The odd but normal

 Odd looking but quite the norm are the corky "wings" of American sweet gum, the rough surface of elms, the flaking papery bark of river birches, and the peeling and cracking bark that falls off in olive, cherry, sycamore, crepe myrtle, Stewartia and Cornus kousa.

American sweet gum

River birch

Crepe myrtle

Cornus kousa

The certainly not normal and caused by an abiotic (non biological) disorder

 Most certainly not normal are lignotubers – a mass of tissue full of small buds which sprout if the treetop is killed or damaged.Burls occur naturally and are an adaptation to fire or other environmental stress.Galls can be genetic, or from insects or disease.Bark may peel and crack off as a result of sunburn. In winter, exposed trunk to warm winter sun rays may force cells to uptake water then freeze and crack at night or in sudden temperature drops. A sunken patch of tree bark is characteristic of sunburn.Bleeding and gumming may occur as a result of a physical injury, pruning or severe water deficit. It may include the release of gums, resins, latex, sap or water.Swelling is a result of additional growth to one particular area - causes include cracks under the bark, girdling, or stock grafts which may be smaller or larger. 

Burl on birch tree

Typical gall tumor

The strange growths caused by genetics

 Flowers may sometimes produce wide flat new growths which are called fasciation.  It is considered a mutation. Wound wood, or callus, is a woody tissue the develops around wounds indicating some previous damage. It retains it differentiated appearance and rarely reverts back to a normal looking bark. 

Fasciation

Wound wood

The responses to a biotic (biological) disorder

 Witches broom in roses ( buds clustering in one terminal branch) are from viruses. 

Viral witches broom on rose

 Swelling with oozing or chaff (small pieces of wood) is usually a biotic condition such as grubs – they dig out the wood to make a burrow and the resulting tissue can swell.Gumming or oozing is usually caused by biotic agents – usually bacteria. 

Extreme gumming on cherry is a sign of a disease

 BEWARE  !!!  If the ooze is pink and smells like a really ripe sewer on a hot summer day - be prepared for the stink of a lifetime !  The culprit is Enterobacter cloacae hence its name - cloaca (an open sewer) – Yuck ! 

Stinky pinkish red slime !

If you see any strange things growing in your garden -

Call Plant Specialists TODAY !

We have experts that know what to do !

They are NYSDEC licensed applicators and can treat them too !!!

Don't delay – the sooner the better !

GREENING NEW YORK FOR OVER 51 YEARS !

   Article written by our Staff Horticulturist, Peter B Morris, BSc, MSc, MBAAll photographs used with permission @SHUTTERSTOCK 

Peter Morris

Peter was born and raised on a beautiful green island in the midst of a tropical rainforest. He was introduced into the world of plants at the age of six when his grandmother, an avid Spanish gardener herself, asked him to help her grow seeds for her pepper garden. He was hooked! By the time he was a teen, he had his own rose and orchid collection numbering in the hundreds. Botany was in his blood, and that is what he set out to study.

His passion brought him to NY in the late seventies to further his education. His tenacity allowed him to work full time at Plant Specialists while he completed a MS in Plant Biology. As a manager at the time he felt unsatisfied with his knowledge of business and business processes. Peter felt compelled to learn, so he then pursued and completed an MBA in Quality Management within a few short years.

Peter’s other passion is teaching. His natural ability is quickly consumed by our staff in all subjects in Botany, Horticulture, and Landscaping. He created an immense reference library of more than 3,500 plants providing an invaluable resource for our staff.

Peter’s breadth of knowledge and wisdom allows him to effectively diagnose the needs of plants. Sometimes just by walking into a garden he can create a prescription that fixes even the hardest issue. He is our Staff Botanist, Diagnostician, and all around Mentor. Recently, he has put his immense knowledge and skills into developing a new department that focuses on Plant Healthcare. As he puts it, “Magic through Science”. The PHC staff that surround him have avidly consumed his teachings. Substantially developing their own plant wisdom, many have taken on difficult plant health issues with spectacular results.

Plant Healthcare has been an instant success with customers! The proper treatment of insects and diseases including Organic methods has made pest control a necessity for every plant. Correcting hormonal imbalances caused by planting in containers or refurbishing soils leached of nutrients by irrigation systems are big challenges PHC has become quite comfortable addressing. The scientific approach to the complex demands of keeping plants healthy in our harsh city environment has made many a customer say WOW!

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