Host an Event Volunteer Join Tickets

Support the plant database you love!

Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?

Share

Ask Mr. Smarty Plants

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants
See a list of all Smarty Plants questions

Please forgive us, but Mr. Smarty Plants has been overwhelmed by a flood of mail and must take a break for awhile to catch up. We hope to be accepting new questions again soon. Thank you!

Need help with plant identification, visit the plant identification page.

 
rate this answer
Not Yet Rated

Tuesday - April 08, 2014

From: Midland, TX
Region: Southwest
Topic: General Botany
Title: How are full sun, part sun, etc, defined?
Answered by: Joe Marcus

QUESTION:

Hello, I have a question about sun requirements. Does saying something needs "full sun" mean a particular number of hours? Does it mean 6 or more hours / day? 8 or more? Is there an agreed upon numeric value for full sun, part sun, and shade? Given that we can fairly accurately model sun conditions now on a site, just curious where the line is drawn. Thanks so much. Love your work.

ANSWER:

There are specific definitions for full sun, part sun, part shade and full shade, but with these definitions there is a healthy dose of art that's thrown in with the science of it.  We define full sun as an area that receives more than six hours of direct sunlight each day.  Part sun is defined as receiving four to six hours of sun each day, while part shade areas get two to four hours of sun daily and full shade areas are defined as receiving fewer than two hours of direct sunlight each day.  However, the mitigating circumstances can be a bit tricky.  For example, afternoon sun tends to be more intense than morning sun.  Sometimes, reflected sunlight can play a significant role in light quality and intensity.  Finally, geography also affects light intensity with desert areas and high-elevation regions having generally more intense sunlight than other places.

 

More General Botany Questions

Fasciation on Texas Mountain Laurel
November 21, 2012 - Do Texas Mountain Laurel normally have a staghorn looking growth hanging on them after blooming in addition to the seed pod clusters or could this be a mutation?
view the full question and answer

Smarty Plants on Wildflowerology
July 08, 2005 - I know there is a word for everything, but I can't find the offical word for the study of wildflowers. Wildflowerology just doesn't sound right. Can you help?
view the full question and answer

Clover in grass in Marysville WA
March 05, 2009 - I noticed clover growing in my grass and know that this is a sign of poor nitrogen in my soil. I would like to know of some native plants / shrubs that I could put near my house in Washington that ...
view the full question and answer

What to do about grass dying under pin oaks in Iowa
December 10, 2008 - We have 2 pin oaks about 15 years old in our front yard. The grass has started dying out under and around them. What can we do?
view the full question and answer

Plants killed by frost
October 31, 2007 - In a frost why do flowers etc. die where grass will not die?
view the full question and answer

Support the Wildflower Center by Donating Online or Becoming a Member today.