March 2022 – The Garden Professors™

Shopping for landscape plants – an illustrated cautionary tale

Flower shows, like this one in Philadelphia, get gardeners excited about buying new plants.

“In the Spring a gardener’s fancy lightly turns to thoughts of…plant shopping!”

If Alfred, Lord Tennyson had been an avid gardener, I am sure he would have included the above line in his poem “Locksley Hall.” I certainly look forward to visiting nurseries and plant centers in the spring to see what new goodies await. But my enthusiasm is tempered with caution – because bad things can lurk in otherwise perfect plants. I posted a four-part series way back in 2009 (the first year of our blog) on inspecting nursery plants.

I strongly recommend you review these posts before you buy – they are 13 years old but the information is still 100% valid.

Split pots, premature burials, suckering and bad pruning – all are associated with poor plant quality and should be avoided by gardeners.

Part 1: inspecting the root flare and trunk.

Part 2: inspecting the roots.

Part 3: avoiding suckers.

Part 4: avoiding poorly pruned young trees.

Today’s post will add some new nursery nightmares to avoid at all costs.

Free complementary gift!

Be sure to carefully check any extra bonus plants…

Make sure you’re buying a cultivar and not a nutrient deficiency

It may be striking, but it’s not healthy.

There are lots of interesting cultivars out there with unusual foliage. This dogwood is not one of them. Interveinal chlororis is a symptom of foliar nutrient deficiency – either iron or manganese – most likely caused by excessive phosphate fertilizer.

Fusion

Fusion can be innovative in music and cuisine. Not so much in plants.

You can’t say they didn’t warn you

If you really want some *Equisetum* there are lots of gardeners who will help you out for free.

Back to nature

It never ceases to amaze me what appears at retail nursery centers. Quality control, anyone?

The scion of grafted plants is rarely as vigorous as the rootstock. Usually you have to wait a few years for the rootstock to take over, but there’s no waiting with these weeping silver birch specimens! But given how hideously trained these trees are, maybe it’s better that they will be slowly subsumed.

Just don’t do it. Please.

Hot glue and paint are for crafts. Not living plants.

Agua Es La Vida.

*No swimming? That’s the last thing we should be concerned about.*

Water is a precious resource and gardeners are often careless with it. Water rationing is a real thing for many of us and, with continuing and spreading drought, may become a reality for many more. Is it possible to have a beautiful garden while minimizing water use?
It is indeed.
[Disclaimer: This blog post is about ornamental landscapes. While efficient water use is also needed for a production garden, the need to produce food is the priority.]

Choose Waterwise Plants
This might seem like a no-brainer but it deserves consideration. As we develop, add to, or change our landscapes we should choose plants that, once they’re established, will thrive without needing additional irrigation. And don’t fall into the “native plants are more water use efficient” trap. Growing any plant outside of its original environment, or planting it in urban or compromised soils in a micro-climate it’s not adapted to, and guess what – native plants can be water hogs too. Carefully considered non-native, regionally adapted plants can use less water once they’re established, provide a healthy environment for wildlife and give you a lovely garden.

*Check plant tags for water use information.*

Group Plants According To Water Needs
This is the only instance I can think of when “companion planting” is a description that works. Group plants with similar water requirements together. And by “together” I mean in a same hydro-zone. If possible, don’t mix plants with different water needs in the same planting bed. Here’s a local example I see quite often: oleander is a popular plant in my area but it needs extra water to be truly happy while Leucophyllum is also a popular plant but needs very little to no extra water once it’s established. A popular landscape combo is oleander as the backdrop with Leucophyllum in the foreground, yet they’re all in the same water zone. So to keep the oleander happy more water must be used but that overwaters the Leucophyllum. And you can imagine the reverse for yourself. In this case, opposites don’t attract.
If you use an automatic system adjust the zones to optimize each plant groups water use. Add, resize, remove emitters or feed lines to help you accomplish this. It’s not a “one size fits all” thing.

Group plants with similar water needs. This photo is an example of how not to plant. The opuntia is well watered, almost too well, yet the petunias in the foreground and the agave in the back left are water stressed. …*Not going to discuss the “pruning” of the sotol and agave. Nope, not going there.*

Monitor Soil Moisture Depth With A Simple Soil Probe
Whether you use an automatic irrigation system, water manually, or depend on the weather, monitoring soil moisture depth should be a part of your garden maintenance routine. We’ve already talked about this in a previous GP blog post so I won’t go into it more here. Just consider this a friendly reminder to make it a part of your gardening routine.

*Soil moisture probes, easy to make or purchase.*

Watch The Weather
Keep an eye on the weather forecast and turn off automatic systems as needed. You can install a rain sensor or “weather eye” on the system but don’t expect it to always work correctly, or at all. You’ll still need to monitor the situation.
And don’t assume just because it rained your landscape received adequate water. Check the soil moisture depth to be sure. If you have containerized plants on your automatic water system you should check their soil moisture levels too. They may not have received enough moisture from that rain storm that watered the rest of your landscape.

*We’re sprinkling in the rain, just sprinkling in the rain…*

Closing Thoughts: Do you really need that automatic irrigation system?
Yes it’s convenient, but is it necessary?
Warning- Anecdotal observation!: After ~20 years of being an Extension Master Gardener and Master Naturalist, working outreach events and phone help lines I’m convinced that automatic watering systems waste more water than they save.
There, I said it.

*Sprinkler overspray, there’s no excuse for this.*

It’s not the fault of the system – it just does what the controller tells it to do. Incorrect installation or placement of feed line/emitters, lack of maintenance, using the wrong emitters for the situation, sloppy programming, and running the system when it’s no longer needed all result in water wastage. An automatic irrigation system is not an install, set and forget thing but it’s usually treated as one. Our goal as gardeners should be to have a landscape that is not dependent on continuous supplemental irrigation. We should lead by example.
If you must depend on an automatic system be sure it’s in good repair, the emitters are the correct type, size and properly placed for the situation and you’ve programmed the controller correctly. Adjust the system as plants grow and mature, this is especially important for trees. Move and add emitters as the canopy and trunk diameter expands.

*Notice the loose bark on the right side of the trunk. There are similar patches on the other side as well. This tree is in trouble.*

*This tree is starting to leaf out but you can estimate the canopy spread.*

*Another view and yes, that is solid sheet plastic you see there.*
*Poor tree.*

“Aqua Es La vida“…”Water Is Life.”
Let’s make every effort to use it wisely and conserve it in all aspects of our lives. Like the song says, “…Don’t it always seem to go that you don’t know what you’ve got ’til it’s gone…”
And by then it’s too late.

More info on efficient water use here:
https://aggie-horticulture.tamu.edu/earthkind/drought/efficient-use-of-water-in-the-garden-and-landscape/

https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=12962

This is a great handout!
https://cals.arizona.edu/extension/ornamentalhort/waterquality/watering_trees.pdf

https://ucanr.edu/sites/UrbanHort/Water_Use_of_Turfgrass_and_Landscape_Plant_Materials/Estimating_Water_Requirements_of_Landscape_Trees/

https://www.epa.gov/watersense/watering-tips

https://www.energy.gov/sites/prod/files/2013/10/f3/est_unmetered_landscape_wtr.pdf

The ABC’s of Plants for Bees!

A yellow flower with a pollen-covered bee resting on top.

A bee collecting pollen from a Black-eyed Susan (Rudbeckia hirta).

Though it might not seem like it for some of us who are still in the throes of winter and it especially feels like a distant dream as I look outside my window here in Montana, but Spring is right around the corner. Along with this magnificent season filled with new life in our gardens and landscapes our world will soon be buzzing with pollinators as well!

Most gardeners have a basic appreciation for pollinators. We know they are responsible for many things including providing important agricultural and economic services by pollinating many of the crops that we eat and by maintaining the diversity of plant communities (which help feed and house lots of other wildlife who share our space). Although lots of animals are pollinators, including birds, flies, beetles, butterflies, bats, small rodents, and more, bees are the most important of them all! This is because they have branched hairs covering their body which make them extremely efficient at carrying pollen from plant to plant.

Honey bees often get most of the publicity when you think about pollinators, or bees in general. Although they are really important to our agricultural operations they are not native but were brought to North America by colonists in the early 1600s. Some gardeners can even name a few additional types of bees but many may not realize the impressive number of bee species that are native to North America, estimated to be around 4000!

We are also becoming more aware of the fact that many wild and domesticated bees around the world have been undergoing declines over the past few decades of observation- which brings up questions about what we can do to help. The cool thing about this is that we, as gardeners, can have a positive impact on our bees, by thinking about them intentionally as we design and plant our gardens and take care of them throughout the year.

Just like us, bees need a few basic things to survive. They need food, a place to live, and protection from practices that can harm them (such as improper/unnecessary pesticide use). Each of these needs can be an entire blog post of its own, and in fact might be in the coming months, but my goal for this specific post is to introduce you to some of the resources that have regional information for selecting plants for pollinators.

Pink flowers with a large bee collecting nectar from them.

A bumble bee sipping nectar from a ‘Pink Spire’ Summersweet (Clethra alnifolia).

Pollinator Partnership, Xerces Society, National Audubon Society and lots of other educational organizations have a vast array of plant lists available for the pollinator enthusiast (see the resources linked at the end of this post to find an appropriate list of hardy plants adapted to your region). As you select your favorites from these lists there are a few things you should keep in mind to ensure you have the best impact on bees with the plants you select:

Add a mixture of different colors, textures, and sizes of flowering plants to attract the largest diversity of bees. Some bees (like long-horned bees, leafcutter bees, and honey bees) are generalists, which means that they will forage on a variety of different flowers. Others (like squash bees and sunflower bees) are specialists, which means that they will usually stick to plants in certain families, genera, and even species. By incorporating a diversity of plants in your pollinator garden, you can also accommodate a larger diversity of bee species!

We know that native plants are an awesome addition to pollinator gardens (because they are well-adapted, and evolved with the native pollinators of the region). That being said, you don’t have to avoid non-native plants altogether. Recent studies show that native and non-native plantings can have a lot of overlap in pollinators. In addition, non-native and native plants will also attract different types of pollinators so you can mix it up!

Make sure there are flowers throughout the growing season by planting things that will be blooming while bees are continuing to forage. Certain bees are active during certain times of the year when they are collecting pollen and nectar for their nests. Having something flowering throughout the year means that a variety of bees can take advantage of these floral resources. Some of the most critical plants that you can select are those that bloom early and those that continue to flower into the fall as the growing season ends. These early and late season flowers are very important because there are fewer resources available for pollinators during the times that bees are getting started (in the early months of spring) and when certain bee species are getting ready to overwinter in the fall. Having these early and late season flowers means that bees will have a source of food throughout the growing season, not to mention the beautiful blooms that you’ll get to enjoy throughout the year.

Stay away from plants that don’t have nectar/pollen sources (like some modern hybridized flowers) or those that have complicated features (such as double petals) which make it difficult for bees to actually get to the nectar source.

Keep these plants safe for pollinators, don’t spray pesticides on plants that are flowering. Or you can wait until the blooms have gone.

Now, you get to enjoy the fun part of choosing plants that are going to add beauty and benefit for pollinators in your yards and gardens.

Large pink flowers, with a bee resting on the side of the petals. Cactus spines in the background.

A bee resting on a Prickly Pear Cactus flower (Opuntia spp.).

Stay tuned for future posts about pollinators and other beneficial insects in the coming months. If you have questions about specific plants, their suitability or pollinators in general, visit the resources below or contact your local Extension Offices for more information.

Resources:

Pollinator Partnership Planting Guides:
https://www.pollinator.org/guides

Xerces Society Plant Lists:
https://xerces.org/pollinator-conservation/pollinator-friendly-plant-lists

Audubon Society Plant Database:
https://www.audubon.org/native-plants

(Some) Fact Sheets about Gardening for Native Bees:

Seitz, N., vanEngelsdorp, D., & Leonhardt, S. D. (2020). Are native and non‐native pollinator friendly plants equally valuable for native wild bee communities?. Ecology and evolution, 10(23), 12838-12850. https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.6826