Best Way to Germinate Baptisia Australis Seeds

Robert Pavlis

Baptisia australis, also called false indigo or false blue indigo, is a native of North America and a great garden perennial. In addition to this species there are a number of other species in the genus Baptisia that are suitable for the garden. Some grow as herbaceous bushes while others are vines.

Germination of the genus seems to be difficult, at least in my hands. A single seedling might germinate, but in many cases none of the seeds germinate. This article summarizes a study conducted to better understand the germination of Baptisia australis seed.

Germinating Baptisia australis from seeds
Germinating Baptisia australis from seeds

Collecting Baptisia australis seeds

The false indigo seeds used for the study were collected in the fall of 2012 and the germination tests were completed in late winter of 2013. The seeds were not all uniformly colored and were of different sizes. Some were a very solid dark brown while others were a lighter tan color. It is presumed that the lighter colored seeds were not as well developed at the time of collection. A mix of different colors and sizes were used for each test. Boyle (ref 1) reported that germination was not affected by seed size, but that dark seeds germinated at a higher rate than tan colored seed.

Germination of Baptisia australis seeds

Once the pretreatment (see table below) was complete for each test, the seeds were placed inside Ziploc snack bags, along with a moistened paper towel. Over the test period of about 8 weeks (12 weeks for cold stratified tests) the paper towel was kept moist with well water that is on the hard side. A large number of seeds representing a couple of hundred species have been germinated successfully in the same way using the same water source.

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Initially most of the test cases were kept in the dark since several internet sources as well as Ontario Rock Garden and Hardy Plant Society Germination Guide suggested that the seeds required darkness for germination. The first seeds to germinate were from test G which were kept in the light, suggesting darkness was not required. In the following table a germination condition of ‘Dark’ means that the seeds were initially kept in the dark for 2 weeks, and after this period they were kept in normal room light during the day, and dark at night. Seeds that were stratified (tests H and I) were kept in the dark during the cold treatment, and in light while at room temperatures.

The seeds were inspected every couple of days for germination. Seeds that had germinated were removed and potted up.

Experiment Design

The following tests were set up.

Test Code # of seeds Pretreatment GerminationConditions % germinated
A 20 Seeds added to hot water and soaked for 24 hour Dark, room temperature 35
B 20 1 week water soak Dark, room temperature 30
C 20 20 min. soak in 25% Clorox followed by a 24 hour water soak Dark, room temperature 45
D 20 4 hour soak in 3% hydrogen peroxide followed by a 24 hour water soak Dark, room temperature 40
E 10

Scarified with a small nick

Dark, room temperature 30
F 10 Scarified with a small nick followed by a 24 hour water soak Dark, room temperature 10
G Approx. 100 24 hour water soak. Water was poured off and seeds were left quite wet in a plastic bag Light, room temperature 30
H 10 Scarified with a small nick Dark, 5 deg C for 6 weeks, followed by room temperature 10
I 10 Scarified with a small nick followed by a 24 hour water soak Dark, 5 deg C for 6 weeks, followed by room temperature 0

Conclusions:

1)      None of the germination methods tested produced a high germination rate. In all cases, a significant number of seeds rotted without germination taking place.

2)      Darkness did not seem to be a requirement, although it is possible that a longer term in the dark might have increased the % germination.

3)      Scarification by nicking the seed coat did not increase germination. The Germination Guide does make mention of rotting following scarification, but this study found rotting in all test cases. Reference 1 found that mechanical scarification (actual method used is not defined) did improve germination t0 96%.

4)      The slowest germination without stratification was seen with Clorox and Peroxide pretreatments. The fastest germination was with test G.

5)      Germination in all cases was erratic, with seeds germinating over much of the test period.

6)      Seeds rotted in tests H and I during the cold stratification period.

7)      A study looking at stratification (ref 2)  without scarification found that germination was increased after 10 weeks of stratification. This case was not tested in this study.

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Based on this study the easiest germination procedure that produces good results would be:

–          In light

–          Room temperature

–          24 hour pre-soak in hot water

A Clorox pretreatment might increase the % germination slightly, but germination does take longer.

Maturation of Seedlings

Getting Baptisia australis seedlings to maturity can be difficult. The post called Growing Baptisia australis from Seed discusses the complete processed used to grow mature plants.

This study was carried out by Robert Pavlis on behalf of GardenMyths.com

References:

1) Germination of Baptisia australis seeds: http://hortsci.ashspublications.org/content/40/6/1846.full.pdf

2) Stratification Improves Seed Germination: http://hortsci.ashspublications.org/content/28/9/899.full.pdf

2) Photo Source: Tony

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Robert Pavlis

I have been gardening my whole life and have a science background. Besides writing and speaking about gardening, I own and operate a 6 acre private garden called Aspen Grove Gardens which now has over 3,000 perennials, grasses, shrubs and trees. Yes--I am a plantaholic!

19 thoughts on “Best Way to Germinate Baptisia Australis Seeds”

  1. I put some Baptisia seeds out in seed trays in seed-grade compost about a week ago, already around 50% are germinated.

    My regime was :

    2 weeks in a refrigerator at 4C, still in the supplier’s envelope
    Rubbed each seed between 2 sheets of sandpaper for ~2mins
    Soaked overnight in hot water
    Planted on top of moist seed compost in an unheated propagator, just covered with vermiculite. Left on a windowsill at room temperature.

    I had the first seed up about 4 days later – I was very surprised because the seed packet said they were difficult.

    Is it more about the freshness of the seed perhaps?

    Reply
    • I think freshness has a lot to do with it. Some seed germinates much better just as they ripen or even before they are ripe.

      Reply
  2. I wonder if I might ask you a question?
    My Baptisia are in mid flower.
    I had some pruning work done on trees and a large limb crushed part of the Baptisia, breaking some of the shoots in flower.
    Can I try rooting them or will leaving them in water allow them to continue to live long enough to get to the pod stage?
    Any advice would be appreciated.
    Thank you,

    Reply
  3. Hi Robert,

    You’ve inspired me to do an experiment of my own with ‘Lunar Eclipse’ Baptisa seeds collected last fall. I’m curious how you landed on 20 minutes for the Clorox soak and 4 hours for the hydrogen soak? I’m planning on testing these as well as a few other household acids.

    This Study:
    https://journals.ashs.org/hortsci/view/journals/hortsci/40/6/article-p1846.xml
    …suggests that the longer the seed is in acid (up to 80 minutes in their test), the better the final germination but it will take longer.

    Curious to know more about your methods,
    Thanks!

    Reply
  4. Thank you Robert – I collected seeds from my garden on Monday March 10,2020 during the rain. I am assuming that they have been stratified over the winter. The seeds were still in the pods and looked fresh. I put them in moistened paper towel, so they got the light and several have already sprouted.

    So my question is can I plant them inside under LED lights until the spring when it is warmer of should I pot them up and put them in a cold frame. I would love to hear your response.

    Reply
    • If the seeds have stayed dry outside – they are not stratified.

      You can grow them either way if they had their cold treatment. how you do this is not as important as the fact that you provide the right conditions.

      Reply
      • The seeds were not dry and I live near Peterborough, Ontario, and it has been cold this winter so I think that they were stratified but not sure. Planted up a pot of 10 sprouted seeds. They are on heat under LED lights. As soon as I see some sprouts I will take them off heat and wait till next month and put them outside. Crossing fingers.

        Reply
        • The Baptisia australis seeds that I collected in early March have all germinated using your method of keeping them on moist paper towel in ziplock bags in the light. I have one have a pot of seeds already in the cold frame and another pot of Baptisia australis under lights that has germinated. I also collected seeds from Baptisia Pink Truffles and the seeds also sprouted in the ziplock bag and I planted them and they too have germinated. The pot of seeds is under lights and growing and they are going into the cold frame soon. Your method works!!! Thanks for posting it. I wonder if collecting seeds early in the spring is the key???

          Reply
  5. Thank you very much for your post. I took what you wrote to heart and decided to employ you Test C case. I expected my germination rate would be less than your 45% because I’m using seeds I harvested 5 years ago. Well, I have at least a 33% germination rate so far. I’ve been surprised by the amount of time it has taken some to germinate (1 week) vs others (5 weeks). Not sure what is going on there but I have 70 little seedlings so far and loving it.

    Reply
  6. Hi Robert. I picked some pods of the false indigo plant and want to sow them. What is the best time of year. I will follow your soak, paper towel method. I am assuming you cannot plant the entire pod, right?

    Reply
    • I plant most of my seed around January/February. It really depends on what systems you have for growing them once they germinate.

      You could plant the whole pod, but I don’t think it would work as well. I also don’t see the point. Cracking it and taking the seeds out is quick and easy for Baptisia and most other seed pods.

      Reply
  7. Hello Robert

    Every spring I find hundreds of seedlings under my Baptisia plant, my difficulty seems to be overwintering – they just seem to disappear Now I am potting some of them up and as you know the plant has a long taproot and I do not yet know if this will be successful

    Reply
    • A friend of mine says she has no trouble germinating seeds, but has problems when she transplants them at the 4 leaf stage. Sounds similar to your problem. I’ll keep an eye on my seedlings and report back.

      Reply
      • My seedlings are now 6″ but 25% suddenly curled leaves and quickly died and not sure if a fungus.. 5 in two pots remain and want to help them survive over winter in my greenhouse.. any suggestion or should I put in our garage to go dormant .. 30 degrees is lowest it gets

        Reply

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