There's Research and Then There's Research

Think you’re the only one who has garden and horticulture questions that need to be answered?

Last week I put hours and hours into reading and research on neem oil. This oil has been around for horticultural use for many years but few, including me, really understand it and how to use it. My insect mentor kept on telling me to stick with the products that contain azadirachtin.

I learned the hard way that most of the neem products in garden centers don’t contain azadirachtin as it’s taken out in the processing. The more I read the more confused I got because so many “sources” online were just simply wrong. The products we buy in garden centers mostly contain hydrophobic neem oil, which has the azadirachtin removed, making the product no better than a light horticultural oil. The lack of azadirachtin actually takes the “magic” out of neem.

When I stopped reading the online garbage that was showing up on Google searches it became very clear that the only products that contain the active ingredient (azadirachtin) of the neem bean or seed is the cold-pressed or pure neem oil. And, after just one use, I began seeing remarkable results in controlling mites, their feeding and reproduction. Even better, the product I bought was organic and cosmetic grade.

The moral of the story is that there is research and there is research. You can’t always tell which is reliable, but when it comes to buying plants I don’t think you can go wrong with what follows:

As I noted last week, a great local resource for gardening and horticultural information is Cornell Cooperative Extension and our local Suffolk County office in Riverhead. But up in Ithaca, Cornell does field trials of annuals and perennials at the Cornell Botanical Gardens. For the most part these trials are of annuals and perennials grown from seed. The trials are done using established scientific protocols, but as a big plus, the trials, which are open to the public, are also evaluated by visitors, which gives a very different perspective.

You can view the trial results here, tinyurl.com/2p88n8es, where there are options to view last year’s trials or you can click on the “trial results” button to see the trial results for at least a decade. This year’s results will be available later in the season. Both Suffolk and Nassau extension offices have done trials, but budget constrains seem to have made those local offerings difficult to sustain.

While many public universities have trial programs it’s important to look at the trials from testing sites that are similar to our conditions out on the East End. So with no good trial gardens on Long Island we have to look at nearby trials, and there is one to our south at Penn State. As with the Cornell trials, breeders send their submissions for what we hope is blind testing, and you can find current trials at the Penn State site here, tinyurl.com/47nu9cuk. These trials include both seed-grown and root-grown stock and are limited mostly to perennials. There are, however, tabs at the top of the page that give you a few options like basket/container or field grown. If you go back to the homepage button you’ll see the trial winners (based on a scale of 1-5) on that page with an option to “See all best in show.”

Going a bit farther south and one zone warmer than us is the Mt. Cuba Center in Delaware that does trials for the mid-Atlantic region. Mt. Cuba does much more extensive research on ornamentals that continue for a number of years. Using this link, mtcubacenter.org/research, click on the research button at the top of the page, and on the right, click on the picture that says “Trial Garden Research,” or on the left, click the button “Read More About our Trial.”

There are some really important trials that you can look at including many of the perennials that can be unreliable and that we have uneven results with in our home gardens. These include Phlox for sun, Phlox for shade, Monarda, Baptisia, Coreopsis, Heuchera and Echinacea plus others. Want Phlox that are mildew resistant? Check here. Echinacea that are really true pollinators? Than this is the site for you.

The Missouri Botanical Garden has an incredible plant database called the Plant Finder, and you can access it here, tinyurl.com/8xhc9v6m. It’s very large and may initially be a little intimidating, but you can choose from over 40 criteria to find a plant for a certain location, soil type, flower color, time of bloom, deer and rabbit resistance and so much more.

Keep in mind that the information in the database is primarily aimed at Missouri gardeners, but under “Zone” you can choose zone 7 to get a more narrow view that can be more appropriate to Long Island. There is also an option for “Plant of Merit” under the “Quick Search” section. It’s a great database to work with when you have some time and need to do serious research on a plant you’ve read about or heard about and need some good or better background on that plant.

Keep in mind that these testing sites have no need to sell you the plants. This makes them unbiased and far more reliable than recommendations you can find in magazines like Horticulture and Garden Gate, where the plants are often advertised or “pushed.”

Michigan State University also does trials that we can look at, and in this case they do annual, vegetables and perennials. To access their trials page use this link, tinyurl.com/9z6tm8ud. Once at the site you can click on the buttons on the right of the page to get general information on how the trials are conducted and other important information including the trial archives that include a rare trial of garden succulents that was done in 2018. Back on the main or initial page on the left-hand side you can get access to three formats of the 2022 trials depending on what device you’re using to view them. The information is complicated and detailed and may not be for the casual researcher.

The Chicago Botanic Garden also has a large plant database that’s available at tinyurl.com/3mwwa523. This will take you to a page that describes the evaluation process for several plants including Echinacea, perennial Hibiscus, an Allium, a Shasta daisy (Leucanthemum) and other fascinating information on how some of these plants were evaluated. At the top of the linked page there is a “Menu” button; on the top right look at the Plant Finder option. This takes you to a very large database where you can search thousands of perennials, trees and shrubs. The information is fairly basic but the pictures are helpful as is the rudimentary information. Keep in mind though that information like bloom time may be general or based on their experience in Chicago. Still a great database to begin with.

If it’s trees and shrubs that you’re interested in knowing about, the job becomes more difficult. Since trees can live for decades and more and can take many years to simply show their form and true growing habits you need an organization that has a proven past and a path toward the future. In this case we have two great resources that have both.

The Pennsylvania Horticultural Society has been around for a while and it’s the organization that gives us the annual and phenomenal Philadelphia flower Show. They also have a great magazine (for members) and a research program. Their evaluation program is simply called the Gold Medal Plant Award and you can access it here, tinyurl.com/4j3yww4b. While also concentrating on the mid-Atlantic I think you’ll find most if not all of their selections appropriate for us. The opening page takes you to their most recent medalists including trees, shrubs and perennials including one of my recent favorites Spigelia.

Back on the homepage on the bottom left of the first screen you’ll see a tab that says, “Explore the Gold Medal Plant Database” and this will take you to the database portal. You’ll have to enter your email address and name to gain access, and I presume this will put you on their mailing list but see no downside to this at all. Once entered you’ll be redirected to the database that has pictures and basic information on each plant. You can search by name or on the left side of the opening database page there are 12 options to narrow down your search. The database is quite extensive but again, with only basic information. You won’t find information on things like insect and disease problems, which are generally harder to find online.

The last resource on my list is the Arnold Arboretum, which is the arboretum at Harvard University in Cambridge, Massachusetts. Their work goes back to 1872 and includes a mere 16,000 plants. If you scroll down on the homepage you’ll find tours of selected arboretum areas in a paginated format done by one of several of their experts. At the top of the homepage on the third column from the right you can click on Plant Search to access their database and under that is a button for searching for plant images. Keep in mind that this is an arboretum so it’s primarily for those wanting to know more about trees but there are some shrubs as well.

Remember that each one of these institutions is supported by subscriptions, donations and endowments. Any one or all of them will benefit from your subscription, membership and donation. Some, Like Penn Hort, also have outstanding periodic magazines and journals. Happy research and of course, keep growing.