Rent Shop Volunteer Join

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 - March 17, 2009

From: Wharton, TX
Region: Southwest
Topic: Non-Natives, Compost and Mulch, Shrubs
Title: Yellow leaves on non-native pittisporum in Wharton TX
Answered by: Barbara Medford

QUESTION:

Green pittisporum that I planted 2 years ago and 1 year ago are getting a lot of yellow leaves. Variegated pittisporum that I planted at the same 2 times are doing fine.

ANSWER:

Pittosporum is a group of plants native to China, Japan and Australia. As such, they are out of our range of expertise at the Lady Bird Johnson Wildflower Center, where we specialize in the use, care, and propagation of plants native not only to North America but to the area in which they are being grown. However, yellowing of the leaves, referred to as chlorosis, can occur in native as well as non-native plants.

Chlorosis is a yellowing of leaf tissue due to a lack of chlorophyll. Possible causes of chlorosis include poor drainage, damaged roots, compacted roots, high alkalinity, and nutrient deficiencies in the plant. Nutrient deficiencies may occur because there is an insufficient amount in the soil or because the nutrients are unavailable due to a high pH (alkaline soil). Or the nutrients may not be absorbed due to injured roots or poor root growth.

If the soil is not draining well, the roots will be inhibited from picking up the trace elements in the soil, especially iron, and that will result in the plants becoming chlorotic. The major cause of chlorosis is a deficiency of one of the essential micronutrients such as iron or manganese. This deficiency occurs not because the nutrients are lacking in the soil but because they are unavailable due to alkaline soil. At these higher soil pH levels (6.5 and above) many trees and shrubs are incapable of taking up adequate amounts of iron or manganese. Central Texas has a lot of alkaline soil; however, some compost mixed into the soil or used as a top dressing often will address the problem, providing better drainage, reducing the alkalinity and improving the texture of the soil and permitting access to the trace elements needed.

Pictures of chlorotic plants.

 

 

More Shrubs Questions

Garden instructions from Austin
June 12, 2013 - I'm a beginning gardener putting in some new landscaping in my front yard in north central Austin, TX. The yard faces almost due east, so it gets full sun until early afternoon, when the house's sha...
view the full question and answer

Plant for full sun behind waterfall
March 21, 2009 - I have a 24 inch waterfall around my pool. I need to plant something behind it. I have full sun and hot Texas weather. I will be watering everyday, so what do you think would grow well in this area?
view the full question and answer

Understory Shrubs for Pennsylvania Clay
December 04, 2013 - I want to replace three non-native Euonymus alatus with native shrubs that will serve as host plants for butterfly/moth species and/or attract bumblebees and other native bees. The shrubs I have are ...
view the full question and answer

Drought resistance of non-native Abelia from Austin
March 14, 2013 - Are abelias drought resistant? I have a spot that is sunny from early morning till about 2-2:30 in the afternoon. Is this enough sun?
view the full question and answer

Shrubs for a Shady Foundation Planting in Texas
February 28, 2015 - We are looking for foundation shrubs, 2-4' mature height, for a totally shaded area which does receive bright light all day.
view the full question and answer

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