Vendor Information on Plant Culture: How Reliable Is It?

Posted by @LarryR on
How reliable is growing information provided by mail order nurseries? Unfortunately, less than you might think.

2013-01-30/LarryR/cc3700

For the last several years I’ve considered purchasing the Louisiana iris cultivar, ‘Black Gamecock’ (see photo at left).  I kept coming back to its listing as I perused this year’s crop of garden catalogs.  It was time, I convinced myself, to give in to the temptation to purchase a plant or two.

My plan was to place an order with one of my favorite mail order nurseries, but I decided to be a bit more scientific than I usually am.  I googled “Louisiana iris Black Gamecock” and studied the first ten mail order nurseries that popped up.  I devised a table with headings that indicated the growing conditions I was interested in and showed which nursery said what about each category.  The table is divided into two parts in order to accommodate all my categories.  It contains a lot of information to try to assimilate in one reading.  I offer an analysis of this information below the tables.  You may want to cut to the chase and scroll down to the heading "Analysis."

THE CULTURE OF LOUISIANA IRIS 'BLACK GAMECOCK'

Nursery

Zones

Light

Moisture

Soil Type

American Meadows

4-9

Full sun

Well-watered, naturally moist

Sandy, loamy, clay

Wayside Gardens

4-9

Full sun, part shade

Moist, well-drained

Normal, loamy

Plant Delights

6-10

Full sun

Moist, up to 4” of standing water

Not listed

Walters Gardens

4-10

Full sun, part shade

Consistently moist, boggy, shallow water

Fertile

Live Aquaria

5-11

Full sun

Bog, up to 3” standing water

Acidic potting soil (grow in submerged pots)*

Miller Nurseries

4-9

Not listed

Well-watered

Not listed

Gardenality

5-11

Full sun to mostly sunny

Moderately to very poorly drained

Clay, loam, silt

Pond Plants and More

6-9

Full to part sun

Water depth up to 3”

Not listed

Nature Hills

4-10

Full to part sun

Moist, well-drained

Not listed

Pond Megastore

3-12

Full sun to part sun

Pond (to 3” deep)

Not listed

*Do not leave pots in water if there is danger of ice forming.

 

Nursery

Soil pH

Bloom Time

Flower Size

Height

American Meadows

Not listed

Early to mid summer

Up to 6”

30-36”

Wayside Gardens

Not listed

Early summer

6”

36”

Plant Delights

Not listed

Early May

Not listed

60”

Walters Gardens

Acidic, pH lower than 7.0

Early to mid summer

4-6”

24-36”

Live Aquaria

Slightly acidic (6.0-7.5)

Not listed

Not listed

36”

Miller Nurseries

Not listed

May-June

4”

24-30”

Gardenality

Acidic, pH 5.5, 6.0, 6.5

Spring –early summer

Not listed

24-36”

Pond Plants and More

Not listed

Not listed

Not listed

12-24”

Nature Hills

Not listed

May to June

Not listed

24-30”

Pond Megastore

Not listed

Late May to June

Not listed

18-24”

 

Analysis

1. Amount of information given by vendor (number of times “Not listed” occurs in a table category)

    Pond Plants and More:  4
    Miller Nurseries:  3
    Nature Hills:  3
    Plant Delights:  3
    Live Aquaria:  2
    American Meadows:  1
    Gardenality:  1
    Wayside Gardens:  1
   Walters Gardens:  0

Walters Gardens is the most gardener friendly in terms of providing the most information and Pond Plants and More is the least.

2.  Zones

    4-9:  3
     4-10:  2
     5-11:  2
     6-9:  1
     6-10:  1
     3-12:  1

Zone recommendations are all over the map, from Zone 3 all the way up to Zone 12.  It is highly unlikely that a single species can thrive in that many zones.  I garden in Zone 5, so according to these results, eight nurseries tell me that I can grow this iris and two tell me that I can’t.  Three nurseries agree that the zone range is 4-9.

3.  Light

     Full sun to part sun:  4
      Full sun:  3
      Full sun to part shade:  2
      Full sun to mostly sunny:  1

Light is the category in which all the nurseries agree most closely, so it’s a good bet that I’ll need to plant this iris in full sun.  One nursery also mentions “part shade” and another “mostly sunny,” but my guess is that, if planted in any shade at all, the iris would not bloom as well.  My gardening experience tells me that sun-loving  plants tend to do better in full sun.

4.  Moisture (Numbers add up to more than 10, due to multiple recommendations by a single nursery.)

     Standing water (3-4” deep):  5
      Moist or well-watered:  4
      Moist but well-drained:  2
      Bog:  2
     Moderately to very poorly drained:  1

The results here make it likely that lots of moisture is one of the keys to success with this plant.  Given the fact that five nurseries recommend immersion in water, I’m a bit skeptical about the advice of the two nurseries who say that the soil should be well-drained.

5.  Soil type (Numbers add up to more than 10, due to multiple recommendations by a single nursery.)

      Not listed:  5
     Loamy:  3
      Clay:  2
      Acidic:  1
      Fertile:  1
      Normal:  1
      Sandy:  1

Five of the ten nurseries provide no information at all in this category.  The recommendations of the others are contradictory.  Descriptions such as "normal” are, I think, the least helpful.

6.  Soil pH (A soil pH lower than 7.0 is considered acidic.)

      Not listed:  7
     Acidic:  3 (PH numbers range from 7.5 to 5.5.)

It is unfortunate that seven of the nurseries provide no information at all for this category.  At least there is agreement among the ones who do.

7.  Bloom time (Numbers add up to more than 10, due to multiple listings by a single nursery.)

     May to June:  3
      Early to mid summer:  2
      Early summer:  2
      Not listed:  2
      Early May:  1
      Spring:  1

Since there is no zone number attached to these bloom times, it is impossible to know which bloom time is the right one for my garden.  Certainly the bloom time in Zone 5 will be later than the bloom time in Zone 10.

8.  Flower size

      Not listed:  6
      6”:  1
      Up to 6”: 1
      4-6”:  1
      4”:  1

Fortunately, there is not a wide disparity here, but it would be helpful to know which conditions produce the largest flowers.

 9.  Height

      36”:  2
       24-36”:  2
       24-30”:  2
       60”:  1
       30-36”:  1
       18-24”:  1
       12-24”:  1

Like the zone recommendations, heights are all over the map.  They range anywhere from one to five feet!  Sixty inches is way out of proportion to the rest of the numbers cited in this category.  That number comes from Tony Avent at Plant Delights nursery.  I know Tony and realize that this is the height he achieves in his wonderful and amazing Juniper Level Botanic Gardens.  However, average gardeners who order this iris from Tony and expect it to grow 60" tall may be sorely disappointed with the height achieved in their own gardens.


So what am I to do with all these numbers and prescriptions?  Will Louisiana Iris ‘Black Gamecock’ thrive and bloom in my garden?  Taking the most frequent response from each category above (noted in green type), the result is:

Zone:  4-9
Light:  Full sun to part sun
Moisture:  Standing water (3-4” deep)
Soil type:  Loamy
Soil pH:  Acidic
Bloom time:  May to June
Flower size:  4-6”
Height:  36”

But frequency is not really a good measure either.  There is no guarantee that, just because one condition is listed more frequently than another, it is the right one for my garden.  So where do I turn now?



I decided to see if there was a society of Louisiana iris growers.  Luckily, there is:  the Society for Louisiana Iris.  Its members are folks who have had lots of experience growing this plant.  Let’s see what they have to say.

SOCIETY FOR LOUISIANA IRIS RECOMMENDATIONS

 Zones  Light  Moisture  Soil Type  Soil pH  Bloom Time Flower Size  Height 
Diverse range of geographical areas; no specific zone recommendations Six to eight hours of sun per day; afternoon shade in hot climates and in desert southwest

Ordinary garden conditions; wet soil; standing water up to 4" deep; even moisture; water very important when blooming

 Richly composted and regularly fertilized acidic soil;  ordinary garden soil Ordinary garden soil (pH not important); acid soil is a must; soil pH of about 6.5 or lower Mid- to late spring (There are early, mid, and late varieties for this time period.)  No specific sizes mentioned No specific heights  mentioned; heights vary from one variety to the next

 

Analysis

Unfortunately, there are contradictions in these data as well.  Is it lots of water or ordinary garden conditions?  Is it ordinary garden soil or must it always be acidic soil?  Is it richly composted and regularly fertilized soil or is it ordinary garden soil?

Light requirements and bloom times are discussed in more detail than is provided by vendors, which is helpful.

Flower size is not discussed.

Height is not specified, but we do learn that it varies among the varieties available.

The website does provide these additional tips, which I appreciate:

The number one rule in acquiring Louisiana irises is to purchase them from reputable dealers.  The number one rule in planting or transplanting Louisiana irises is to prevent their drying out.  Plants are normally shipped in the early autumn because that is when the plants are coming out of their summer doldrums and getting ready to spurt into growth.

Given their preference for even moisture, Louisiana irises respond well to being mulched. Mulching has the added advantage of regulating fluctuations in soil temperature, and it also protects the rhizomes (which often grow right at the top of the soil line) from the dreaded sunscald and the extreme temperatures.

During the hottest of the summer months most Louisiana iris will go into a form of semi-dormancy. If you keep adequate water to them during this time and ensure that their rhizomes are mulched you will find that they should maintain some foliage during the period.

When the worst of the summer heat has passed you will notice that your Louisiana iris will start into their most active growth cycle. Once you notice the growth of new rhizomes you should start a fairly vigorous regime of fertilizing for the next six to eight weeks. Don't be tempted to give your iris one big feed and leave it at that. You are much better off to give them a good feed quite often instead.


So what have I learned from my Louisiana iris research?

•  Do not rely solely on growing requirements listed by any one mail order company.  They may vary greatly from vendor to vendor, are sketchy, can be contradictory, and thus are often not very helpful.

•  Louisiana irises seem to need lots of moisture and mulch, especially during the hottest part of the growing season.  I'm skeptical about them doing well in ordinary garden conditions.

•  The conflicting statements by the Society for Louisiana Iris not withstanding, the 7.0 pH level in my garden soil is probably not detrimental to this iris, but I will fertilize exclusively with acid fertilizer.

•  The Society's website says nothing about hardiness zones, but does indicate that some varieties have been successfully grown in North Dakota and Massachusetts.  Based on that information and on the first two tables above, ‘Black Gamecock’ is probably hardy in my Zone 5 garden.

•  Don’t worry if my iris goes semi-dormant in the heat of summer.  It is not dying.  If it is planted in a garden bed, keep watering it during this time.

•  Once the weather cools, feed my iris regularly for six to eight weeks.

Past experience tells me that the unreliability of growing information from vendors is not restricted to Louisiana irises, although the number of contradictions I found here may be an extreme example.  If there is no local gardener experienced enough to tell you if a plant you want to acquire will grow well in your garden, check to see if there is a society for the plant you are interested in purchasing and follow its growing recommendations. Be prepared for a few contradictions.  You may not find an answer to all your questions.  Among the advantages of plant society websites is the fact that you are dealing with actual, experienced gardeners and not with vendors.  And you can communicate with its members to find answers to your questions.

When the next research mood strikes, I'll check out several more plants and see what vendors have to say about them.  Stay tuned.

 

Endnote:  Thanks to Sharon, a zone 6b gardener, for the photos of 'Black Gamecock' (above and at left).  She reports that she soon discovered this iris likes moisture and full sun.  She is fortunate to have just such a spot in her garden.  Hot, dry summers in her area take a toll, but the iris survives them.  It blooms in late May and benefits from a regular addition of compost.

For reliable and extensive information on a particular plant, try the ATP plant database.  As I write this, there are 540,631 plants and 149,979 plant images in this amazing compilation.  It is a work in progress, so not every plant has a complete entry at this point.  On the other hand, there are 176 plant categories, from "Abeila" to "Yarrow," that are customized to give you even more information.  Check out the daylily database to see what I mean.  Click here for information on daylily 'Tic Tac Toe.'

Are you a vegetable gardener?  Check out the incredibly detailed Garden Planting Calendar here.  Learn when to start seeds, when to transplant them, and when to direct-sow them.  Click on a vegetable name to get detailed information on its culture.

 

 
Comments and discussion:
Thread Title Last Reply Replies
Like everything these days by crittergarden Mar 1, 2013 2:52 PM 4
Interesting by Xeramtheum Mar 1, 2013 10:19 AM 6
It's an adaptable plant by dyzzypyxxy Feb 27, 2013 9:52 PM 0



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