Explore Plants

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
    
 

Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.
Need help with plant identification, visit the plant identification page.

rate this answer
Not Yet Rated

Friday - June 10, 2011

From: Loveland, CO
Region: Rocky Mountain
Topic: Trees
Title: Are junipers tainting the soil in Loveland CO?
Answered by: Barbara Medford

QUESTION:

Have several varieties of junipers around my yard. Each year I try to place a small garden in a corner of my yard, the plants don't do well at all. Growing up nearby, I gardened with my parents so I have a good basic knowledge of gardening. When we were at Travis AFB in California I found out that the eucalyptus tainted the soil. Do junipers do something similar? Thank you

ANSWER:

We did some research and discovered no instance in which eucalyptus, which is native to Australia and therefore out of our range of expertise, poisons soil. We did, however, find this article from the U. S. Fish and Wildlife Service Environmental Containment Program Eucalyptus Trees Used to Clean Up Selenium in California. Since you say you were in California, perhaps this is what you heard about.

So far as we know, neither does any member of the Juniperus genus poison the soil around it. We don't know which members of the genus you have, but the ones native to Colorado are: Juniperus communis (Common juniper), Juniperus communis var. depressa (Common juniper), Juniperus monosperma (Oneseed juniper), Juniperus osteosperma (Utah juniper), Juniperus scopulorum (Rocky mountain juniper), and Juniperus virginiana (Eastern red cedar). You can follow each plant link to our webpage on that particular species of Juniperus, and read the information about its use and care.

The next question is: Are you trying to plant that garden under those junipers? From a previous Mr. Smarty Plants answer:

"As for the Juniperus ashei (Ashe's juniper) on your property, there is some disagreement whether anything will grow under them. Again, you have the heavy shade, and the litter of needles, berries and twigs always on the ground, which will discourage many plants and inhibit seedlings. 

From this article  Biology and ecology of Ashe Juniper by F. E. Smeins and S.D. Fuhlendorf, we extracted this paragraph on the allelopathy of the Ashe juniper:

'There is little evidence that the accumulated litter of Ashe juniper in any way alters the chemical nature of the soil as it relates to growth and development of other plants (Yager 1993). Soil chemical and physical properties are in fact "improved" by the presence of the juniper litter (Marshall 1995). No allelopathic effects have been shown to be produced by the litter. The major impact of the litter seems to be its physical presence and its alteration of hydrologic properties of the area under the canopy. The thick litter layer is a difficult physical medium for seeds of other species to germinate and grow in mainly because moisture either runs off (due to the hydrophobic nature of the litter) or it dries out very quickly after a precipitation event, which prevents seedling growth from reaching the mineral soil (Yager 1993).'

'Junipers create an environment under their canopy.' They do indeed. That environment includes dense shade and a lot of shed material like leaves, berries and bark (aka mulch).  Add to this that the shed material is hydrophobic ( it sheds water rather than absorbs it) and I ask you what could be less conducive to existing plants?"

You need to till the litter from the junipers and oaks into the soil and plant natives appropriate for your area, soil, light, drainage and enjoy. The juniper is considered a nurse plant for many plants that grow below it and bask in the conditions.

Now, here is the catch-did you note we said "plant natives?" If you are trying to grow plants not native to your area of Colorado, you may be blaming the juniper for something that is not its fault.

 

 

 

More Trees Questions

Need suggestions for a privacy screen besides Murray Cypress.
October 18, 2011 - Mr. Smarty Plants, I live in NE TX, about an hour east of Dallas on I-20. I hear interstate traffic behind my house, and have a busy street on its left side, and a school adjoining in back. I thi...
view the full question and answer

Registered/patented pecan by Foster W. Fort
August 01, 2010 - Hello, we own a historic house museum once owned by the Fort family of Waco, and have learned that Foster W. Fort developed a type of pecan tree and had an orchard somewhere here around Waco (possibly...
view the full question and answer

Plants for winter installation in Houston
January 01, 2009 - What plants can you plant in the winter, Houston, Texas?
view the full question and answer

Repairing damage to Anacacho Orchid Tree in Austin
April 30, 2008 - Hi You Guys!! We have an understory Anacacho Orchid Tree in the front and my sweetie was trimming the big oak and dropped a branch down, splitting one of the large branches off the Anacacho. The wou...
view the full question and answer

Native Plants for a water collection pit in Bronson, FL
August 22, 2013 - I live near Gainesville, FL in a low rural area with many cypress swamps around & bought this 5 acres 2 years ago. About 15 years ago a pit was dug on my 5 acres to give the rainwater somewhere to go...
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.