Strange Fruit: Oak Galls

Native oaks (Quercus spp.) are keystone species for insects and the ecosystems in Georgia. Over 550 species of Lepidoptera (butterflies and moths) use them as a host plant, and their larvae (caterpillars) are important sources of food for birds and other predators. Other insects rely on oaks too and sometimes their use of oaks creates growths that might appear to be flowers or fruit. These growths are the plants’ response to the egg-laying activities of small wasps or midges. According to this article, there are around 800 different types of galls to be found on oaks in the US/Mexico/Canada areas.

I have seen a number of different types of oak galls in my area and I have pictures of some but not all of them. I will supplement this post with photos from others (each image is credited unless it is mine). Perhaps the most noticeable of the oak galls in my area is the Wool Sower Gall. When it is at its best, it is a fluffy white ball with red spots created at leaf buds. Identification groups get dozens of requests to identify “this tree” when the galls are prolific.

Wool Sower Gall on white oak (Quercus alba)

Some galls are leaf galls – meaning the tiny insects lay eggs in the leaf – while others are stem galls. A friend of mine recently found an excellent example of a mid-rib type of gall, perhaps the Clustered Midrib Gall Wasp (Andricus dimorphus).

Mid-rib leaf gall (D. Lane photo)

Another fairly noticeable type is the Oak Apple Gall. By the time most people find it on the ground where it fell, it is a lightweight, papery husk.

Oak Apple Gall (Joe Boggs photo)

One year there was an abundance small, hard red galls that look like aborted fruits. The identification groups in Georgia got numerous questions on what tree produced these.

Small galls that look like fruits (wasp larva in center)

In researching for this article, I found great information on an Ohio website. It contains a number of articles on the different types of oak galls. It is one of the few sites that presents information without trying to give guidance on how to kill them. 

Most galls seem harmless to the tree, but some can cause minor twig damage. None are fatal to the host plant. The diversity of shapes and sizing is incredible. Look out for galls on your oak trees and be amazed at what nature can do.

A Collection of October Posts

 

This blog is seasonal. Every week the topic has something to do with what’s happening: in the yard, in the season, even what’s happening with me. For those of you who haven’t been following since day 1 (Mapleleaf viburnum: October 14, 2010), you can still enjoy the posts by scrolling through the archives on the right side of the blog.

I find it entertaining to occasionally go back and see what I posted about in the same season, even in the same month. October can be such a good month for being outdoors, enjoying an abundance of fall flowers, and delighting in the beginning of the fall color season. Here are a few of my favorite October posts over the last few years.

October is a great time to fall in love with our native asters. I have posted about them several times over the years, highlighting the different species in my area (with more in this post too) as well as tried to demystify the species of small white ones. Not only are asters number two on the list of keystone perennials, but they also are huge sources of late season nectar and pollen for native bees and butterflies. Add more to your garden!

New England aster

It’s a good time to evaluate or appreciate what you have in the home garden. Is your garden supporting the fall migration of butterflies like the Monarch? This post highlights some fall nectar plants (spoiler alert, it mentions asters as well as other plants). This earlier post is similar but you might find it inspiring.

Monarch on Blue mistflower

Other posts that seek to inspire you include this one with the Lorax to remind us that we have the power to make change in a positive direction. This next one specifically talks about including host plants for our native butterflies. It has a printable chart. This third post is your reminder to be diverse in the garden, not just for host plants but for nectar too.

If you’re just done with flowers and want to bask in the glow of the trees, here are two posts for you. One is about planting native trees that give you double duty or the more recent “Get a Tree That Does More.” Dreaming about driving up to the mountains for leaf-watching? Bring It Home: Fall Color gives you ideas for having good fall color in your own yard.

 

Talk to Your Neighbors about Native Plants

As we learn more about the benefits of using native plants, it is natural to want to spread that information to neighbors, friends, and family about why it matters. What I’ve found is that people are surprisingly open to learning more but usually appreciate help in making changes. Here are some ideas for spreading the native plant message among friends. 

1. Introduce the idea: You might play off areas of interest like birds (“I noticed you like to feed the birds”) and butterflies (“I love butterflies but I haven’t seen many this year, have you?”) and then talk about how native plants support them better. Explain about how you learned that diminishing landscapes with native plants have contributed to declines in birds and insects and that you’ve been swapping out some of your plants to help them. 

2. Validate how people feel if they mention specific plants. “I loved that as a child but now I know that it doesn’t support our insects.” “Now I know that using a native plant is more helpful.” “You know, when we know better, we can do better.” Use my food chart example to illustrate that we don’t have to get rid of all exotic plants.

3. Explain terms like exotic and invasive to convey that only some exotic plants are a problem. Include concepts about how the bad ones can disrupt the ecosystem and that wildlife/wind/water spread your seeds to other places; it's not always obvious to the person who has the plant.

4. Address concerns (Won't it be messy?). We know that we can use design principles to have aesthetically pleasing gardens with native plants. Encourage people to take it one step at a time and not be overwhelmed. 

Example of intentional design

5. Provide information like resources from the Georgia Native Plant Society and Homegrown National Park. Share social media groups (Facebook), people to follow (Instagram, TikTok), blogs, and podcasts that you have found helpful. 

6. Offer to help if you can: help dig up old shrubs for older people or offer to help research some ideas for replacements or where to buy them. Share some of your favorite native plant extras!

Feel free to use my graphics and my blog posts to illustrate concepts or provide recommendations. Spread the word!

September 2024 Moment in Nature

The diversity of native insects is amazing. I am always thrilled to find a less common one. This week found me leading a walking at Stone Mountain (where the number of Stone Mountain daisies was woefully down!). As we came down the trail we found a pair of walkingstick insects on a sign. What a way to brighten our day! It is definitely my #momentinnature for this month.

Walkingstick insects (there are two)

After some light research, it would appear these are the common walkingstick, Diapheromera femorata. These insects are herbivores. You can read more about them here.

Keep your eyes out for cool stuff! And if you're also missing the sight of Stone Mountain daisies (Helianthus porteri), here a photo from another year.

Helianthus porteri, an annual native sunflower

Ferns of Georgia

 

There are over 100 ferns native to Georgia and the Southeastern US. Some are big and bold while others are tiny, single-frond plants. Some spread on their own while others clump in a very tidy fashion. Like many native plants, some have evolved to live in special conditions (wet areas, rocky outcrops); quite a few of them are garden suitable and I’ve written about those Georgia ferns before. 

Christmas fern

Christmas fern (Polystichum acrostichoides) is one of our most well-known species for dryish shade; it is native to most of the state except for the coast; I profiled it in 2018 and included some landscape usage photos.

Recently I attended a talk about native ferns at our local chapter meeting. The speaker had a copy of a useful reference book that I had not seen before: Ferns of Alabama. Plants don’t follow state lines and there is a huge amount of overlap between the two states so this a good companion to our Georgia reference, Field Guide to the Ferns and Other Pteridophytes of Georgia. 

The books are not new; the Alabama one is 2012 and my copy of the Georgia one is 1986 but they apparently updated in 2003.

Both references have good introductory sections that I encourage folks to read because they give you a better understanding of how these plants grow (physical details of fern growth), how geology and geography affect what ferns grow where, as well as identification details for the different fern families.

The Georgia book has line drawings only but they are quite excellent, often including some important detail of the sori (reproductive structure). The Alabama book has line drawings as well as photographs. The Alabama book requires you to turn the page to see all the photos/text associated with one species, meaning that if the book is open then you might be looking at the description for one species and the photos of the previous one. I find that potentially confusing. The Georgia book shows everything on the same page spread.

Neither book has the latest Scientific names (and that is true for printed materials in a changing world), but the old name is easily cross-referenced using a resource like Flora of the Southeastern US (New York fern, as an example, is now Amauropelta noveboracensis, but you can easily use the old name Thelypteris noveboracensis to find the new name).

If you’re using these as a field guide, each book includes a natural range map by county, indicating where they grow in the wild. Each of them includes a few exotic ferns that have naturalized (although they don’t include one of the more recent naturalized ferns that I profiled in 2022).

I encourage you to get to know the ferns of your particular area and consider using them in your landscape for both beauty and functionality. While the ecosystem usage of these primitive plants is not as obvious as the host plants we use for insects, they serve as attractive and useful plantings, especially in shadier areas.

Prioritize Removal of Invasive Plants

 

Georgia roadsides are a mixed bag of vegetation but increasingly they are being swallowed up in invasive plants. In Georgia, we’ve all seen mounds of kudzu, stands of bamboo, thickets of privet, choking wisteria, and trees transformed into English ivy monsters. Joining them now are the large-leaved Princess trees, colonies of tree of heaven, thorny ornamental pears, chinaberry, mimosa, tallow tree. All of these are Category 1 invasive plants in Georgia. These plants are literally overtaking native plants, reducing the productiveness of our natural ecosystems, resulting in fewer pollinators, fewer birds, as well as other critters that depend on these.

Roadside English ivy, spreading towards neighbor

In this post I present 3 ideas that we could implement to help slow up these invasive plants.

I used to think that development would at least help clean some of this up. But that is not always the case; several newer neighborhoods near me kept all those road edges intact. New homeowners there appear to like the buffer that these thickets of privet and tree of heaven provide. The fruits and seeds from these plants continue to infest new areas, creating an even bigger problem.

Building approvals that should require developers to remove Category 1 invasive plants as a condition of the permitting process. With a smart phone in every hand, identifying invasive plants is not hard to do and should be part of the cost of development just like water management, roads, and utilities.

Kudzu, despite our knowing how bad it is, is actually worst now that before. Infested areas are spreading rapidly to new properties and seeds are dispersed even further. Why should property owners have to deal with the neglect of others? I am aware of one Georgia community that is drafting a ‘control of vegetation’ ordinance to require owners to manage invasive plants, especially when they move into adjacent properties due to lack of control: “An invasive plant owner shall not allow an invasive plant that is capable of spreading by runners, roots, vines, stems, bulbils, or rhizomes to spread from the invasive plant owner’s property to any public right-of-way or any adjoining property not owned by the invasive plant owner.”

Municipalities that manage their roadsides are capable of exerting the effort to actually remove invasive trees that grow into utility lines; unfortunately my personal observation is that they just prune them, ensuring that they will need another round next year while also allowing them to set seed and shade out native plants.

In summary: 1) require developers to remove invasive plants during construction; 2) create ordinances that require owners to contain any spreading invasive that they have; and 3) remove invasive plants in the right of way as part of regular roadside maintenance.

Kudzu overtaking a wooded park (those trees all have kudzu)

Great Southeast Pollinator Census – Year 6

The Great Southeast Pollinator Census is a fun citizen science activity that helps people get more acquainted with their local pollinators. It also helps them see which plants get good insect activity.

Pollinator census capture of skippers in love

I like to count in both the morning and afternoon to see how the pollinator activity changes. I enjoy watching how the different pollinators behave: for example, bumble bees move fast while carpenter bees lumber and prefer to crawl from flower to flower if they can.  

Every year that I do the census, it makes me think anew about how my pollinator garden can be more successful. In my 3-part pollinator series, I talked about several factors for supporting the most pollinators: using regional plants, providing for succession of blooms, having more than one of the same plant, and using different plants for different pollinators. If you haven't read it, dive into part one, part two, and part 3 at the hotlinks.

Red admiral on Joe pye (Eutrochium)

Eastern Tiger Swallowtails

This is the sixth year of the census; it has expanded from Georgia-only to now include NC, SC, and FL. You are welcome to see my reports from the previous years, starting with 2023 (it has links to the older ones). Because the count is held during the same general timeframe each year, you'll see that I count on the same types of flowers each year (and I'm always amazed at well they support pollinators). It is clear from my counts that I have a really healthy bumble bee population!

Ailanthus moth on Rudbeckia laciniata

Bumble bee on Silphium

Carpenter bee on Silphium