En EspaŅol

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
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

Wednesday - November 22, 2006

From: Leander, TX
Region: Southwest
Topic: Propagation
Title: Breaking dormancy of native seeds
Answered by: Nan Hampton

QUESTION:

The science of seed preservation seems to be well advanced. However, Jill Nokes' book appears to be the only well-known information about breaking dormancy of native seeds. I'm grateful that she wrote that book, but it is more of a anecdotal collection than a scientific study, so I would appreciate any further sources of information that you encounter. If you can answer, or forward this question to the appropriate person, I would certainly appreciate it: Is stratification, either warm or cold, a biological process that requires imbibation in order to proceed? In other words, should a seed be scarified BEFORE stratification? This is confusing to me because all texts seem to treat storage SEPARATELY from preparation for germination, while in nature it's all one complex, variable process. Obviously, since my objective is to propagate, I need to perform specific actions at specific times to replicate the "natural" requirements of a species. More than you expected, I guess........, but thanks for any help.

ANSWER:

Seeds with tough impermeable coverings need a break in that seed coat in order to allow moisture to enter to begin the germination process. Seed scarification occurs naturally from environmental sources—abrasion from the soil, frost, fire, passing through the digestive system of animals, etc.—but this is more or less a random process. We can intervene and speed up the process by scarifying batches of these tough-coated seeds before they are planted. There are several methods: mechanical—abrading by sandpaper, knife, etc.; soaking in water; and treating with acid. Stratification, either cold or warm, involves storing the seeds in a moist medium, such as sand, for a period of time to break the physiological dormancy. Indeed, seeds with tough coats need to be scarified before stratification so that they can take advantage of the moisture in the stratification medium. Several studies have reported both increased speed and amount of germination by scarifying and then stratifying seeds. For example:

Kaye, T. N. "Effects of scarification and cold stratification on seed germination of Lupinus sulphureus ssp. kincaidii." Seed Science and Technology (2001), v. 29(3), p. 663-668. A combination of scarification and stratification increased germination by as much 95%.

Syn,. Y. C. et al. "NaOH scarification and stratification improve germination of Iris lactea var. chinenesis." HortScience (2006 June) v. 41(3), p. 773-774. Germination improved by 80% using both treatments together.

Geneve, R. L. "Seed dormancy in Eastern redbud (Cercis canadensis)." (Jan. 1991), v. 116(1), p. 85-88. From the abstract: "Seed dormancy in Eastern redbud (Cercis canadensis var. canadensis L.) can be overcome by seedcoat scarification to allow water imbibition, followed by chilling stratification to permit germination."

Qrunfleh, M. M. "Studies on the hawthorn (Crataegus azarolus L.): I. Seed germination as influenced by scarification and stratification." Dirasat Series B Pure and Applied Sciences (1993) v. 19(4), p. 7-18. Acid scarification combined with warm stratification increased germination by 10%.

Stratification requirements and techniques differ for various plants and some do not benefit particularly from stratification. However, if the seeds would benefit from stratification, either cold or warm, and they have an impermeable coat, the bottom line would seem to be scarify first and then follow with stratification.

You can find a good article on seed germination and dormancy from Texas Tech University Department of Plant and Soil Science.

 

More Propagation Questions

Can I Grow Beautyberry
December 30, 2011 - Will try to be brief. Beautyberry sprouted leaves in vase of branches in water. It's NYC beginning of winter. Can I plant it outside? If not will it grow in a pot inside? Thanks. Happy New Ye...
view the full question and answer

Is slow growth of young Tx mountain laurel normal?
July 02, 2012 - My Texas mountain laurel is 2 or 3 years old and is about 4 feet tall. It seems quite healthy but has grown very little, if any, and has never bloomed. Is this normal? Although I don't want it to gro...
view the full question and answer

Proliferation of Small Palafoxia in Dallas Co. TX
June 07, 2013 - A few years ago I noticed a new wildflower I hadn't seen before in the southwest Dallas County area. I found the name to be Small Palafoxia. It was growing along the edges of HWy 67 in Duncanville ...
view the full question and answer

Propagation of Texas bluebells from seed
July 29, 2008 - I have a few Texas Bluebell seeds. I would like to grow these in my yard. What would be the best place..pot or flower bed? When should I plant? How to maintain?
view the full question and answer

Germination of Purple Clematis from Junction TX
October 31, 2013 - I have some Purple Leather Vine seeds I want to share and want help learning to germinate. Can anyone there help me find interested recipients?
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.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP | STAFF
© 2015 Lady Bird Johnson Wildflower Center