Sunday, March 17, 2019

So You Want to Support Pollinators – Part 3

This is the last in a 3-part series on changing at least some of your landscape to support pollinators. The first part (here) was about understanding the benefits of doing so. Last week we covered ‘how to start,’ which included evaluating your space and researching/choosing your plants. Note: there was a mistake in the charts for Part 2; those charts have been fixed now. As we head into the season of spring native plants sales in Georgia, you’ll want the list of plants you’ve chosen handy. 

You’ve picked your spot and figured out how much sun and moisture it has. You’ve researched your plants and made a list of what you plan to use. Now it’s time to lay out the design. Here are some things to consider:

Grouping plants: Bees, in particular, are better supported by groups of the same plant. Rather than plant one of twenty different things, include 3-5 of each species and plant them in a group so the pollinators can move from flower to flower. Grouping is also more aesthetically pleasing to humans so your design will be attractive to your neighbors as well. Knowing the mature size of the plant will allow you to place them far enough apart to give them room without going further than necessary. For a fuller look, plant closer together but recognize that you might adjust (i.e., move them around) as they reach mature size. Draw out your design on a piece of paper so that you remember what you planned when it comes time to plant.

An example of a design where each number represents a different type of plant

Leave space for ground nesting bees: Leave a few bare areas off to the side so that ground-nesting bees have a safe place to make their nests. These aren’t yellow jackets that I’m talking about, but small, solitary bees that provision for a few eggs and then leave the larvae to grow up on their own. See more information at this link and good pictures at this link.

I noticed this ground-nesting Colletes bee in 2014

Now you can buy your plants! Here are some things to consider:

Source: buy from reputable native plant suppliers, including special spring sales that groups use for fundraising and small, local nurseries who are trying to make a living by growing native plants.

Size: perennials usually come in quart and gallon size; consider the value for what you’re getting, check for bloom buds (know that quarts may not bloom the first year but you might be able to buy more of them) and good root growth. A gallon-sized plant might have just been stepped up from a quart and isn’t any older than the cheaper quart.

Pesticides: ask if the plants were grown with neonicotinoid pesticides; these are harmful to insects and can even have residue present in the nectar and pollen as well as the leaves for the first year. We don’t want to attract pollinators only to harm them.

Prep the ground just before planting by removing any weeds or grasses, amending with compost if you like, and leveling or mounding the ground to fit your design. Install the plants so they are no deeper in the ground than they would have been in the pot (don’t over-dig the depth of your holes or they may sink after being watered). Lightly loosen the roots if they are bound and spread them to the sides to encourage them to explore their new home. Gently press the soil around each plant to reduce air pockets.

I also like to include a few rocks for butterfly basking and for small lizards/salamanders to hide under.  You might even do a puddling station for the butterflies. Adding a tall stick/pole is helpful for dragonflies that might like to visit (and eat a few mosquitoes). Modest amounts of untreated mulch/pinestraw (don’t use the colored mulch, it has chemicals) help retain moisture but leave some un-mulched areas on the edges for ground bees. Water your plants after planting.

Protect your new garden from the harsh realities of nature! Water your plants as needed the first summer and fall if you don’t get sufficient rain. Protect from any deer as needed; I use Liquid Fence but there are other protects and methods to deter them.

The next step is the fun part: Observation! Keep a journal to record what you see, what is doing well, what you wish you had more of, or what did poorly. By sharing your experience with others, you might get more ideas for plants to add in the fall (more native plant sales!).

Left: Southeastern blueberry bee, Center: Tiger swallowtail (dark form); Right: Longhorn beetles 

Here are some specific maintenance tips to consider going forward:

  1. Re-evaluate during the blooming season if your thoughts on light and moisture turned out to be not quite right (too much or too little).
  2. Re-evaluate for quantity and placement of plants (are the big ones crowding out the small ones, do you need more milkweed).
  3. At the end of the season, lightly tidy as needed but leave as many stems, seed heads, and foliage as you can; these harbor small insects for birds to eat during the winter. They may also contain the chrysalides of butterflies.
  4. Come spring, clean up foliage but leave 10-12 inches of stems from the bigger perennials. Stem-nesting bees will use them to harbor the next generation: the year of 2019’s living stems are used in spring of 2020 to make nests and those bees will emerge in spring 2021 (see my previous blog here). I take any foliage that I remove and lightly create a stick pile in a shady area; that way any bugs have a chance to safely emerge.
Have fun, learn from your mistakes, and shout your successes for new people to learn.

Newly planted area in 2014; it is now overtaken by tiny asters and this
Penstemon smallii is nowhere to be found in this bed! Things grow and change.

Sunday, March 10, 2019

So You Want to Support Pollinators - Part 2

Leaf cutter bee on Rudbeckia fulgida
Last week I wrote about understanding the benefits of changing your landscape to support pollinators. I laid out the basics of the concept: knowing the difference between needing food (larval host) plants and nectar plants. If you missed that post, you can find it here. This post is about How to Start, specifically evaluating your space and choosing the plants.

For those of us in Georgia, now is a great time to be planning. Spring native plant sales start in about 2 weeks so you’ll have plenty of opportunities to pick up the plants you chose for your new space. Before we pick out any plants, however, we’ve got to understand the space. The two most important considerations are the physical conditions of light and moisture.

Light – the range of light varies with the location (North-facing, South, etc.) as well as any nearby tree canopy. Most pollinator gardens want to maximize blooms so we’ll want a location that gets good sunlight. Full sun conditions are defined has having 6 or more hours of fairly direct sun each day. Whether you get sun hours in the morning (the kindest of lights) or the afternoon (harsh light) or a combination of both, the total hours in the growing season (when nearby trees have leaves) needs to be at least 6.

You can measure your light in the area on a sunny day when you are around all day. A clever method that I read about has you put down a marker for every hour that you go outside and the area has full sun; you can use popsicle sticks, utility flags, marbles or even just mark it on a piece of paper. Go outside at the same time each hour and check. Then count up all your markers to get the number of sun hours. If the area varies (half of it gets 6 hours but the other half gets 5, for example), then make a note that you might be choosing part-sun plants for the shadier half.  You may have to re-evaluate during the blooming season if there are a lot of trees that cast more shade than you thought.

Moisture – while most basically broken down in wet and dry, we know that there are places in between those two extremes. There are locations that are consistently moist, others that are soggy after a rain (but dry out later), and some places that are generally average-to-dry all the time. This is hard to evaluate in a day; you’ll need to have a longer period (or perhaps you already know).

Turtlehead (Chelone glabra) is good for wet spots and bees love it

Once you’ve evaluated the physical conditions of the chosen site, it’s time to pick the plants based on those conditions and the pollinators that you want to support. My recommendation is that you choose your plants based on no less than 4 points: light requirements, moisture requirements, appropriately native to your area, and bloom time. If you have a specific pollinator goal (e.g., you want to support Monarch butterflies), then add a 5th point for that goal.

Silver-spotted skipper on wild bergmot (Monarda fistulosa)

Two of those points need further discussion: appropriately native to your area and bloom time.

Appropriately native – these are plants that you know are native to your area whether it is the Piedmont region or the Coastal Plain or the Mountain eco-systems. These plants evolved with the insects in your area and, in the case of butterflies in search of larval hosts, will likely support what’s flying around. For example, gardeners in the Piedmont aren’t expecting to have the deep south-based Palamedes swallowtail butterfly visit so would not plan to include red bay (Persea borbonia) as one of their host plants. You can research ranges for certain plants using USDA, BONAP, and the Georgia Herbaria.

Bloom time – good pollinator support needs flowers during all 3 seasons: spring, summer, and fall. Luckily, we have a good selection of native plants that bloom in all those seasons. Please don’t forget the fall, especially if you want to support migrating butterflies like Monarchs. They need those flowers to power their trip back to their overwintering locations. Goldenrods, many of which are well-behaved, are an essential part of fall blooms.

Golden ragwort (Packera aurea) is an early bloomer

While I certainly put most of my emphasis on native plants, some non-native flowers are heavy bloomers and might be included as part of the mix in your garden to add extra floral power. These include plants like zinnias, tithonia, and pentas as long as they were grown without pesticides. Other people like to include the non-native herbs parsley and fennel as host plants for Black swallowtail butterflies (note: Black swallowtail is the only butterfly that uses it, not ‘all swallowtails’).

In March of 2014, I published a blog with 3 full lists of seasonal native plants for North Georgia. Here is the blog if you want to read it, or use these direct links to the 3 lists:

Here’s an example of a plant that I would choose for my garden with all 5 points considered: Black-eyed Susan (Rudbeckia hirta) is a full sun, average/dry moisture, native to my area, blooms in summer (late June into early August), and supports small bees and small butterflies.

I hope you are now on your way to evaluating your space and researching your plants. Here are some reference sources for determining host plants for butterflies and moths if you want to support the larval host needs of particular species:

Jaret Daniels’s book ‘Butterflies of Georgia
David Wagner’s book ‘Caterpillars of Eastern North America

Tiger swallowtail on Asclepias tuberosa

I love it when a plant can do double duty, something mostly unique about native plants. Here a dark Eastern tiger swallowtail butterfly nectars on orange butterflyweed (Asclepias tuberosa) which is the larval host plant for Monarch butterflies.

The next (and last) installment in this series will be about implementation and maintenance; look for that post next week.

Sunday, March 3, 2019

So You Want to Support Pollinators – Part 1

As more information becomes available about pollinator declines (and insects in general), people are inspired to think about how they can make changes to their landscapes in support of them. I’ve agreed to give a talk this summer about this topic so, if you don’t mind, I’m going to use the next several blog entries to flesh out what to say to people who are eager to listen.

Monarch on blue mistflower (Conoclinium coelestinum) in the fall

Benefits – people want to know why it’s worthwhile to put the effort into choosing specific plants for pollinators. What pollinators are likely to benefit? Is there any other reason to consider doing this?

  1. Bees – while many flowers can support bees, there are some flowers that especially support native bees and others that are more nutritious and healthy for bees in general.  I loved finding the southeastern blueberry bee in my garden several years ago. In addition, the concept of native bees as distinct from honey bees is getting more attention. Besides what you plant, your pollinator garden design can increase your support of native bees.
  2. Butterflies – adult butterflies enjoy many flowers while butterfly (and moth) caterpillars have more specific requirements and these requirements are usually native plants. If you’d like to have more butterflies swirling around your garden, planting what the caterpillars need is a way to keep ‘em coming.
  3. Birds – supporting birds is a bonus side benefit of pollinator gardens. Seed-eating birds like goldfinches are grateful that you planted coneflowers and sunflowers. Insect-eating birds (and parents with hungry chicks) enjoy some of the bugs (that is, pollinators) who visit your garden.
Megachile bee on Rudbeckia
Southeastern blueberry bee

Basics – it all comes down to several key choices when deciding how to populate your pollinator garden. You’ll want food and shelter. When it comes to food, you’ll want it to be pesticide free and you’ll want a selection of both host as well as nectar plants. I like to say that the nectar plants bring them in and the host plants convince them to stay (and lay eggs). Plant choice makes a difference:

  1. What are host plants? Another term is ‘food’ plants and they are the plants on which butterflies, moths and other bugs will lay their eggs. One of the most well-known examples is the Monarch butterfly and its host plant milkweed (Asclepias sp.) and related plants in the milkweed family (Asclepiadaceae). You have two options for where to locate your host plants:
    1. In your pollinator garden – these are chosen specifically to be a part of your pollinator garden and are usually perennial plants: the milkweeds for Monarchs, the pussytoes for the American ladies, pea family members for skippers, passion-vines and violets for fritillaries, etc.
    2. Near your pollinator garden – these include trees and shrubs that are located in the area around your garden: spicebush for spicebush butterflies, sassafras and tuliptree for tiger swallowtails, plus oaks, cherries, elms and others.
  1. What are nectar plants? These are the flowering plants. Some might flower only in one season (spring/summer/fall) but return each year so they are considered perennials. Annual plants may flower throughout several seasons and are generally showier. Over time you might observe that different bees and butterflies like different flowers; this is usually because of the length of their tongue:
    1. Short-tongued bees, small bees, and small butterflies like skippers use smaller flowers and flowers with shorter floral tubes. These include the flowers of milkweeds, asters, goldenrods, coreopsis, sunflowers, mints, etc. Some flowers are simply for crawling inside: turtleheads and penstemons make for great bee-watching as bumble bees scoot in and out of the flower itself.
    2. Long-tongued bees and butterflies with long proboscis (as well as hummingbirds) prefer flowers with long tubes like cardinal flower, sages, native azaleas and vines like native honeysuckle, crossvine, and trumpet creeper. 
    3. You'll want a variety of flowers to satisfy different pollinators.
Bumble bee shares coneflower with caterpillar
Andrena bee on hawthorn

Next week we’ll talk about How to Start, including evaluating your space and conditions as well as choosing your plants. Part 3 will cover implementation.

Sunday, February 24, 2019

When Plants Take Over

Unlike a rambunctious vine such as kudzu, plant invasiveness is not always immediately apparent. This is the time of year that the wild spread of ornamental pears (Pyrus calleryana) in Georgia, however, is especially apparent. White-blooming trees on the side of the road this time of year are not native; we don’t have trees (in North Georgia anyway) that bloom this early.

Ornamental pear (Pyrus calleryana) wildlings

People might think this is a bonus. “It’s nice to have these blooming trees so early!” And it would be if the plants weren't invasive, spreading into areas and crowding out what native plants might have been there. These trees create dense foliage and replace native trees like maples, redbuds, sassafras, and serviceberries that would naturally grow in the part-shade woodland edges. These pears only provide one kind of support to insects: pollen for bees which are often non-native honey bees. Unlike native trees, they provide no services to insects the rest of the year, such as for butterfly and moth larvae. Insect diversity suffers when one plant takes over.

When do we know that something has become invasive? How does it start? It usually starts with cultivation which introduces the plant into ornamental landscapes (yards, parks, etc.). Sometimes the cultivated plant (developed by nurseries for traits like better flowers or fruits) is actually promoted as ‘sterile,’ meaning that it won’t set fruit (really they are just self-incompatible, not actually sterile as has been proven since then). This was true when ‘Bradford’ pears were sold beginning in the mid-1960’s (the nurserymen must have realized that the tiny fruits were a problem if they felt that declaring it ‘sterile’ was a plus?!).

Leftover fruit on callery pear tree
Once enough of them are in the broader landscape (enough of them for pollinators to fly between), plants exchange generic material (pollen) which makes many of them have a better fruit set.

Japanese honeysuckle (Lonicera japonica) is an example with many years of history. Collected from Asia in 1804, cultivated in the US by 1842, 'improved' in 1862 ... the first documentation of its escape to the wild was in 1882. By then, it had been planted in thousands of gardens. It is now considered to have invaded more acres in the southeastern US than any other non-native plant (including kudzu which is more noticeable but on far fewer acres).

It doesn’t take a math major to figure out how things multiply into increasingly large numbers. My neighborhood has a large amount of non-native mahonia (Mahonia bealei). In the 15 years that I’ve lived here, I have removed on average about 3 seedlings a year. That’s not much, right? If I hadn’t, however, I’d now have 45 plants in my two-acre yard. Each one would be flowering and creating more. I have neighbors with large amounts of this plant (one is even proud of how many he has). Each year, they spread further down the road, as birds eat the fruits and fly just a little bit further.

Instead of having mahonia, my woods have more blueberries, more native azaleas, more viburnums and other native shrubs. I have more diversity than if I’d let this plant grow as often as it showed up.

Same with the callery pear: every year, fruit gets carried just a little bit further by a bird, a squirrel or even a human. We should absolutely stop planting it and stop selling it. Just as important: we should be removing these escaped plants, because every one of them adds to the multiplier effect. These wild pear plants are especially fruitful. Please remove any that you find. Support our native insects by making room for native plants.

This blueberry (Vaccinium) is native to my yard and it supports insect herbivores

Sunday, February 17, 2019

This One’s for You

The dimpled trout lilies (Erythronium umbilicatum) started blooming last week; I came home from a business trip on Thursday, Feb 7 and one clump already had flowers. It was wonderful to see them, as always, and perhaps just a smidge earlier than last year where my first picture has a date of Feb 11. It’s always a race between them and hepatica (Anemone americana, formerly Hepatica nobilis  var. obtusa) to see which shows up first.

Dimpled trout lily (Erythronium umbilicatum) 2019

This early sign of spring is much loved by me and many others. One of my friends died this week after being suddenly diagnosed with late stage cancer. The dimpled trout lily was one of her favorites. As a volunteer for the National Park Service and the Georgia Botanical Society, she spent many hours leading field trips in February and March to places where the trout lilies bloomed.  Chattahoochee River National Recreation Area was a favorite area and she would showcase the trout lilies there at Cochran Shoals/Powers Island and at West Palisades/Paces Mill.

Dimpled trout lily (Erythronium umbilicatum)
She also liked to help people get native plants into their gardens, and she used her role as a rescue facilitator with the Georgia Native Plant Society to help people rescue trout lilies that were in the path of construction.

Land conservation was also important to her and so she was very happy when Wolf Creek Trout Lily Preserve in South Georgia was saved in 2009.

She leaves behind a lot of friends inspired by her joyous love of nature and tireless zeal to encourage others to know, love, and conserve it. For me, the dimpled trout lily will always remind me of her. This one’s for you, Maureen.

Sunday, February 10, 2019

Removing Invasive Plants Makes a Difference

Many of us have worked on invasive plant removal projects from time to time. It’s a satisfying experience to see a choked woodland opened up to opportunities for native plants to return and thrive. We don’t often get the opportunity to see the benefits of the removal, particularly on insect populations, but we hope and trust that nature will rebound. Recently, a friend shared a link about a study completed in 2013 in four areas “within the Oconee River watershed in Northeast Georgia that were heavily infested with Chinese privet.” The results were just what you hoped they would be: “These findings provide justification for allocating resources for invasive shrub species removal to support long term conservation of these important insect groups and the ecological services they provide.”

Privet (Ligustrum sinense) thicket at a stream

Privet (Ligustrum sp.) is a serious invasive pest in the Southeast, with large populations in forest land (over 1 million hectares in 2008) as well private land and roadsides. Another upcoming invasive shrub in my area is Elaeagnus sp., and I’m starting to see very dense thickets of it forming where humans take no action to control it. Both of these affect the amount of light and open ground (for nesting bees) in an area and reduce the amount of sunlight available to native herbaceous plants, reducing the diversity of plants and pollinators.  There are some who would argue that privet flowers themselves support bees, but “Although privet may be an abundant floral resource in late spring, heavy infestations with dense shrub canopies severely limit abundance and richness of pollinators by decreasing availability of sunlight.”

I am including some of the interesting parts of the study; feel free to read it directly at the source here. The detail, resources, and references are worth exploring.

The study measured pollinator populations 5 years after removal of the privet in the study areas (completed by 2007 after cutting in 2005 and treating sprouts in December 2006); the study was completed in 2012. The study areas differed on how the privet was removed: by either mechanical mulching or hand-felling. The sampling method for this study is described as: “Bees and butterflies were sampled for one week out of each month from March to October 2012 on mulched, hand-felling, control, and desired future condition plots.”  The information collected in 2012 was compared to a previous study in 2007 on the same plots. “This is the first study showing that these immediate responses of the pollinator communities to disturbance continue for at least five years despite secondary plant succession.”

So for those of you out fighting the good fight – keep fighting. It’s worth it to the creatures that need us the most.

Sunday, February 3, 2019

Nature’s Winter Resilience

Rhododendron copes by rolling up its leaves
Georgia experienced some cold overnight temperatures this week; while not our lowest (I have seen 5 degrees here before), temperatures did go down to 21 degrees two nights in a row. As I went outside to refill the bird feeder, I noticed that some of the evergreen plants that I bragged about in last week’s blog were looking quite bad. Surely they were goners?

In the case of the alumroot (Heuchera americana) in a pot by the door, the wide leaves looked almost black and shriveled. I walked around a bit to look at some of my other broad-leaved evergreens like the ginger (Hexastylis shuttleworthii), and shrubs like Florida anise (Illicium floridanum) and rhododendron (Rhododendron sp). They were definitely affected by the cold. 

Heuchera americana looking pretty bad in a pot by the door

How did the needle-leaved evergreens look? I checked out the hemlock tree (Tsuga canadensis) to see how its needles were faring. Skinny and covered with a light waxy coating, they showed no difference from how they look in above freezing temperatures.

Luckily nature copes, either by design of the leaves (like the needle-leaved evergreens) or by being able to rebound. Once the temperature reaches above 32 degrees, the leaves on the broad-leaved evergreens return to normal. The Rhododendron and Illicium leaves uncurl and plump up as if nothing had happened. The leaves on the Heuchera were amazingly recovered as well. I truly admire nature’s resilience, but then I guess she’s been doing this for a very long time. Which is good because the Georgia groundhog just predicted six more weeks of winter ....

Heuchera americana as the temperature exceeds 32 degrees - magic!