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

Friday - April 17, 2015

From: Wyndmoor, PA
Region: Mid-Atlantic
Topic: Soils, Shade Tolerant, Grasses or Grass-like, Herbs/Forbs, Shrubs, Wildflowers
Title: Plants for a Shaded Slope in Philadelphia
Answered by: Anne Van Nest

QUESTION:

I have a small slope along the North side of my house in a suburb of Philadelphia. A small maple tree grows there but most of it gets no sun at all (a large segment is under the tree). I had the soil tested at Penn State and it is very acidic. Last summer I added nitrogen/phosphate just like it was recommended from Penn State but I think the rain probably just washed it all away. It was very very dense soil. So my questions are 1) how to I prepare such dense soil for planting and 2) what specific grasses/sedges/small shrubs/herbaceous plants do you recommend?

ANSWER:

Let’s start first putting together a list of native plants for your area. Take a look at the Native Plant Database on the www.wildflower.org website and put in the following search criteria: State = Pennsylvania, habit = herb (for herbaceous), duration = perennial, light requirement = shade, soil moisture = dry.  Then select the height you desire. This will generate a list of herbaceous plants. Do the search again for grasses and grass-like plants and shrubs to add to your list. 

The nitrogen that you added last summer is water soluble and has probably leached away. Penn State Extension has information online about the 12 soil regions of the State. Philadelphia is in the Coastal Plain soil region.

Coastal Plain

The soils of the Coastal Plains section developed in coastal sands. These soils usually have a sandy surface texture and are well drained. Because the topography is level, erosion potential is typically low. The soils contain few rock fragments but have moderate root zone available water content due to the coarse soil texture. This region has the longest and warmest growing season of Pennsylvania. Most of the area is occupied by the city of Philadelphia and its suburbs.

Melissa Miles, Philadelphia Sustainable Agriculture Examiner has published an article in Examiner.com about determining your soil type. She says that most soils in Philadelphia are characterized by a heavy clay content and describes a simple test to determine this and how to use the soil triangle.

And to amend your clay soils, The NC Cooperative Extension Service has an Urban Horticulture factsheet on Amending Clay  Soils with many good tips such as “Adding organic soil amendments to the soil lightens soil texture, discourages compaction, adds nutrients, improves drainage and aeration, moderates soil temperature, and provides pore space, which is essential to plant growth. Clay without organic matter is like a flattened deck of playing cards. Adding organic material jumbles the cards, permitting water and oxygen to enter the soil.”

 

More Herbs/Forbs Questions

Color in non-native portulaca from Beach Haven NJ
July 21, 2011 - I bought a portulaca in a hanging basket and divided it up and planted it in my garden. It is doing ok..but I have almost entirely orange flowers..maybe two reds. I was hoping for multi-colored..red...
view the full question and answer

Hillside Erosion Control for Gainesville GA
August 07, 2013 - I have a steep bare hill and the runoff from it is heavy this year. I need help with a fast growing groundcover that will help control erosion and runoff. Planting on the hill is difficult because you...
view the full question and answer

Project on natives in Connecticut from Chino CA
April 13, 2010 - Hi Mr. Smarty Plants, My 10 yr. old daughter is doing a project on Ct., and would like to know what the most common plants, trees and flowers are found in this state. A few of each would be a great ...
view the full question and answer

Plants to grow between concrete pavers on the patio in Rock Hill, SC..
December 31, 2014 - I have a patio of concrete pavers, about 2 feet by 2 feet each. It gets very little sun. No morning sun at all. The zoysia grass we have between the pavers now does not grow well at all. Do you ha...
view the full question and answer

Research on Atriplex confertifolia in Austin
January 21, 2010 - I have heard a lot about Atriplex confertifolia (Shadscale). Has the Center done any research/trial growing of this plant for possible adaptability to Hill Country (west Austin) area? If this is a ca...
view the full question and answer

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