SENESCENCE AND MARCESCENS

Design and InstallationFirewoodGarden Caregarden TriviaIndoor plantsPlant Health Care
Written By Peter Morris

Normal Leaf drop

 

Usually, older leaves throughout the plant turn yellow to straw colored, then drop. The plants may look as if in decline but will fill up with new green leaves as new growth continues.  The change in coloration is always the clue!

 

A gradual color change progression is normal in natural leaf shedding

 

Several common landscape trees and shrubs have physical or physiological traits that resemble a disorder but in fact they are fine ! Leaf shedding (senescence) and leaf retention (marcescens) many times cause confusion because we don't see them as common or they are seemingly out of season. 

 

Senescence

 

Natural leaf shedding is often mistaken for a disorder in evergreens. Depending on the species, evergreen leaves live for one to several years, shed at different seasons, and shed influenced by environmental factors. Arborvitae in spring and summer. Magnolia usually in summer, and Pines and Cedars in fall.

 

Arborvitae drop their older leaves in Spring and Summer

 

Pines drop their needles in the fall

 

Marcescens

 

Fall leaf retention in deciduous trees is normal only for some oak species and occasionally beech. These are considered evolutionary adaptations that actually benefit the trees. Take a look under an oak tree covered in retained leaves – what you see is lots of bird poop on the ground – fertilizer!  Birds tend to congregate in Oak trees that have densely retained their leaves.  

There are also botanists that believe the leaf retention is to deter browsing animals to eat small twigs and branches if these are covered in dead leaves. Some think the retention is due to poor soil conditions.  I myself like the bird poop theory !

 

Beech tree will many times retain its foliage

 

Abiotic Disorder 

 

Marcescens on any other species is considered an abiotic disorder (abnormal) and is usually water deficient related.  Sometimes also caused by sudden freezes or a disease that suddenly kills off a branch.  

 

Taxus suffering from fungal root rot looses the ability to uptake water and dries out!

 

An extreme and quick water loss (it dried out!) will cause the same look on any tree or shrub during the growing season. In essence, the leaf died and got stuck on the branch before the natural process of leaf dropping occurred.  The natural process of leaf dropping never had a chance to start !

 

Late spring freeze damage new growth which remains stuck on the branch

 

 

If your leaves are dropping out of season - Call Plant Specialists TODAY !

Our Plant Health Care Team can check them out for you !

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, MBA

All 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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