It was a beautiful day and I took the opportunity to go out and take a few pictures in the empty lot next to my office. Although we had a lot of rain this winter and early in the spring, April has been relatively drier than usual (at least that’s how if feels, I haven’t checked the actual data). Nevertheless, the drainage pond that is usually dry in the summer was about has high as it can be without the entire upper area being a bog. In a slightly higher part of the area I found quite a bit of this little corn speedwell (Veronica arvensis) growing. It’s a native to Europe and has been introduced widely in North America (according to the US Department of Agriculture, it can be found in every state except North Dakota, and I wouldn’t be surprised if it’s actually there, too. The blooms are quite small, only about a quarter inch across, and are a lovely blue color. As weeds go, there are worse.
Tagged With: Non-Native Plant
The flowers on this plant, Iris domestica, the blackberry lily, don’t really give much clue to their common name. When they go to fruit, however, it’s a little clearer where that comes from. They do have a certain blackberry-like look to them. The flowers are a bright orange and are really lovely. The leaves are very iris-like and are beautiful, sculptural fans of varying shades of green. In fact, I’d be tempted to grow these even if they leaves were all they provided. But the flowers are welcome and I like the fruit, as well. We scatter these fairly liberally around the garden and they are now coming up in various places. They aren’t so aggressive that we worry about them taking over, either, which is nice.
I have had this Clivia for quite a few years now, since a coworker left it to me when she stopped working here. I had it at home for a while but two years ago I brought it to my office and it’s been doing pretty well. It gets literally no direct sun light with my north-facing window but it seems to be doing well with that. They don’t tolerate frost and are grown as houseplants here but they must be wonderful in a garden in their native South Africa and Swaziland. The blooms, as you can see, are quite bright and vary a bit from the orange seen here to yellow and nearly red. Thank you, Emily, for this long-lasting gift.
Cathy and I went for a walk near Lake Frank today, parking on Bauer Drive and walking in through a break in the houses (there’s a lot that’s not privately owned) and then along the road that leads, within the park, the the parking area. That road and parking area are not in use and haven’t been for many years although I’m not entirely sure why. It was a pleasant walk and we enjoyed the late autumn colors reflected in the lake as well as the oriental bittersweet (Celastrus orbiculatus) in a few places. I don’t recommend growing this, but I have to admit it’s pretty.
This is one of the more prevalent weed shrubs in our area. The Amur honeysuckle (Lonicera maackii) is an east Asian native that has firmly established itself as noxious weed in the eastern half of North America. It’s got the sweet, tubular flowers typical to honeysuckles, starting out white and aging to yellow. They are followed in the fall (right about now, obviously) by bright red, juicy berries. Although they are inedible to humans, birds eat them and spread the seeds far and wide. They were once planted as an ornamental and you can see why. However, they are no longer recommended, because of their invasive nature.
There are places where English ivy (Hedera helix) looks really nice. It’s also a very good ground cover for many situations. Nevertheless, I’m not a huge fan. In a city, where it can perhaps be contained reasonably well by paving, etc., it’s suitable. In the suburbs and rural areas it can really be an annoyance. This ivy is growing up a tree near my office and you can see how it grips its host. It will grow up into the tallest trees and eventually strangle them. It also covers the ground so completely that in often chokes out less aggressive plants (and there are only a few more aggressive). We’ve done our best to eliminate it from our yard and with a small patch that seems to reappear occasionally, we’ve succeeded. But we remain on DEFCON 3 or higher.
The woodland forget-me-not (Myosotis sylvatica) is blooming in our back yard. Cathy planted these and they have spread to various places, mostly in the lawn, and they are very pretty little things. Similar to the flowers of the Virginia bluebell (Mertensia virginica) he buds are pinkish purple and the flowers change to blue as they open and mature. Also, the little white “eye ring” around the center change from white to yellow. They are delicate little flowers and although they are not a native species, they are lovely and don’t go to crazy in our yard, so I don’t mind.
This will start blooming in a week or so, but even before it’s in bloom, sweet woodruff (Galium odoratum, also known as sweetscented bedstraw) is quit pretty. In fact, I’d say this photo doesn’t do it justice. The shades of green are just lovely and it makes a really nice groundcover where you don’t need something evergreen. We have a few patches of this and I really like it where it is. It isn’t too aggressive and it fits in very nicely. When crushed, it gives off a strong odor of freshly mown hay, even more so as the plant dries.
The plant this gooseberry flower is on was one that Albert had growing in his yard. Brady left me dig it up before she moved out of that house and it’s done very well against our back fence. Dorothy made little tarts with gooseberries from it last year and it looks to have a pretty good crop again this year, if the number of flowers tells us anything. The flowers are generally considered insignificant, at least from an ornamental standpoint. They are quite small and not particularly showy except from very close but they are actually pretty little things. The gooseberry (Ribes uva-crispa) is native to Europe, N. Africa, and the Caucasus and is, as you’d guess, primarily grown for it’s wonderfully tart fruit. The leaves of gooseberries contain hydrogen cyanide, a toxin that, in sufficient quantities, is pretty bad for you.
The lily of the valley (Convallaria majalis) is starting to bloom. We have it in a few places around the yard and these are at the front corner of our house where they get just a bit more sun than the other places so are a little ahead. It’s a lovely plant and has lovely, sweetly fragrant flowers but all parts of the plant are very poisonous so if that makes you nervous, you might want to avoid it. It contains cardiac glycosides, “a class of organic compounds that increase the output force of the heart and increase its rate of contractions.”
We dug some up in a yard that was being torn up when a road was being widened and it was growing through asphalt paving, so it’s pretty tenacious. We have it in a fairly large bed in the back yard but it is actually being forced outward by Vinca minor which I wouldn’t have thought possible.
Dusty Miller (Jacobaea maritima, a.k.a. Senecio cineraria) is a marginally hardy, herbaceous perennial. It’s hardy here, anyway. We have it growing in an urn-shaped container near the end of our driveway and it seems happy enough. It does have flowers but they are not particularly ornamental and many people prune them off so as not to distract from the foliage, which is what the plant is generally grown for. It does well in both shade and sun and really takes very little care.
Cathy and I took a walk in the neighborhood this evening. That’s been something we’ve done a lot more of since we can’t really go out as we once did. Spending time outdoors is important for mental health, I think, and particularly in the spring when the weather is so nice, it’s a real blessing to be able to get out. These are the leaves and flower buds of a Photinia × fraseri shrub around the corner from our house. As you can see, the new leaves are red and it’s quite a striking plant, particularly when growing in full sun, where the color can be even more stunning. Photinia × fraseri is a hybrid of P. glabra (Japanese photinia) and P. serrulata (Taiwanese photinia).
It’s a week early for Mother’s Day but we’ve been cooped up for too long and we didn’t want to wait until next week. We took our annual trip to Fehr’s Nursery early this afternoon and Cathy bought a load of plants. As usual, I wandered around and took photos of flowers, etc. I got some nice pictures of various hens and chicks (Sempervivum varieties) including some Sempervivum arachnoideum, which have what look like cobwebs on them. I decided to go with this photo, however, of lady’s mantle leaf (Alchemilla mollis ‘Auslese’) with water droplets on it.
The Star of Bethlehem (Ornithogalum umbellatum) is a pretty, little, but invasive bulbous plant native to Europe, northern Africa, and the Middle East. It’s coming up in our back yard and we really should do something about it, although it’s hard to want to pull out something as pretty as this. I’m not sure where it came from as we only have it growing in our lawn and not in any of our garden beds. This time of year they just appear in the lawn. Our mower is out of commission until I get a new carburetor so the grass is getting long but once that’s running again, these will be mowed along with the grass.
I know I’ve already had a picture this spring of the lily of the valley (Convallaria majalis) from our garden but it’s blooming so well and so long that I thought I’d share another. We’re also in a little lull where there isn’t a lot new coming out, although it’s still changing. So, here’s another view of the little white bells of the lily of the valley, this time from the back garden, near the fence (not that it makes much difference, of course). Soon the flowers will be gone and even the leaves will fade in the coming heat of summer. We are near the southern limit of where it grows well. If you grow it here, it needs some shade to protect it from the heat of the summer sun but further north it does well in full sun.
We also have a terrific crop of Canadian thistle (Cirsium arvense) coming up among it (and many other places, as well) and it really needs to be dealt with. That’s a really problematical weed, having “a deep and wide-spreading root system with a slender taproot and far-creeping lateral roots.” (Source: Fire Effects Information System, US Forest Service). That same document also says that “new plants can also form from root fragments as short as 0.2 inch (6 mm),” which helps explain why it’s so hard to get rid of.
Last year, after getting rid of the stump from the Colorado spruce that I cut down, we planted a hawthorn to one side of the bed and Cathy planted some perennials as well. Two of them are a variety of Spanish lavender (Lavandula stoechas) called ‘Anouk Supreme’. They are blooming now and they are quite lovely.
Each individual inflorescence is nice, as you can see here, and overall the entire plant is really nice, with lots of blooms. The individual flowers are a very deep purple and the bracts at the top are only slightly less intense. Both the leaves and the flowers give off that wonderful lavender aroma that we’re all so familiar with.
We haven’t done terribly well with plants like this in the past but I think this is a good location for them. If they do well, I’d be happy to get a couple more. We also have a rosemary that we might put here with them. This species of lavender is native to the Mediterranean countries including France, Spain, Portugal, Italy and Greece.
One of the plants Cathy bought on our annual Mother’s Day trip to the nursery (a week early this year) was this blood flower, Asclepias curassavica ‘Silky Red’. As you can see, the colors are pretty intense. This species of butterfly weed is native to the Caribbean and Central and South America and is only winter hardy to USDA zones 9 to 11, so we grow it as an annual here but it’s worth it. The butterflies and other insects love it and even without that, it’s just a beautiful flower. If you have a very bright indoor location (or a heated greenhouse!) then you could bring it in for the winter, but we just start new each year.
Many years ago my dad gave me a subscription to a thing called The Seed Guild. The idea was that this guy had relationships with botanical gardens and arboreta around the world and had worked out an arrangement where he collected seeds from them and distributed them to Seed Guild members. I don’t remember the details but I do know the seeds for this lilac came from there. The catalogs I have (from the late 1990s) list three species, Syringa amurensis, S. josikaea, and S. wolfii, so I assume it’s one of those three. I’m leaning towards the last of them, which may more properly be known now as Syringa villosa subsp. wolfii (C.K.Schneid.). I had it growing in a container for many years and it never got very big. When we moved here in 2006 I planted it in the back garden and now it’s about 8 feet tall and obviously doing well.
This is yet another tender perennial grown here as an annual. It’s a non-vining, morning glory-like plant native to Brazil. It’s a member of the convolvulus family (a.k.a. the bindweed or morning glory family, Convolvulaceae) but it doesn’t twine and the genus, Evolvulus, means to untwist or unravel. This variety, ‘Blue My Mind’, has beautiful, pale, sky-blue flowers about an inch across. This does really well in hanging baskets or other containers and that’s where this is destined to go, but so far it’s among the plants waiting to be potted up.
I took pictures in the yard earlier today but then Cathy and I went to Meadowside Nature Center and took a walk there. Since most of my pictures this spring have been from the yard, I decided to feature a photo from off-site today. We walked from the nature center down to the creek (North Branch Rock Creek) and from there to the lake. We could see the eagle’s nest and at one point saw one of the juvenile eagles sitting on the edge of it. We stopped and sat by the edge of Lake Frank and I took some photos of these yellow flags (Iris pseudacorus), growing on the shore. They are native to Europe and western Siberia, the Caucasus, and northern Africa. They’re quite lovely and I particularly liked the way these were shown against the grey of the very still water. We enjoyed watching the swifts or swallows skimming around over the lake. We heard a barred owl a few times in the distance.
It’s kousa dogwood (Cornus kousa) time in the neighborhood. These trees bloom later than the native flowering dogwood (Cornus florida) and in general have fewer problems here. They make quite handsome trees of a good size for a suburban yard. They flowers are followed by interesting fruit so they have two seasons of interest, which is nice. They also have interesting bark. The main thing, though, is that they aren’t killed by dogwood anthracnose, which is pretty hard on the C. florida trees. C. kousa is also a bit hardier, although that’s not a real issue here. But the disease problem really is.
I really should plant more of this as well as other ornamental onions. This is Allium moly, often called golden garlic, and it’s a lovely little bulb, blooming later than many of the spring bulbs. Its flowers are smaller than daffodils but it makes up for that by being one of the few things in bloom right now. In theory it spreads and needs to be controlled when growing in ideal conditions. Clearly that’s not what it has here, but it seems happy enough. Another Allium that I’ve had but don’t now is Allium caeruleum, which has pale blue flowers. I think I’ll order some of that, too, this fall, along with a bunch more deffodils.
This is a pretty little flower that’s starting to appear in our garden. It is Dianthus armeria, the so-called Deptford Pink, native to Europe and not naturalized over much of North America. It is an annual or biennial and grows between two and three feet tall with very thin stems topped by these lovely little pink flowers, which are about a centimeter across. It self seeds pretty well but isn’t aggressive enough to be a problem at least in our garden. Most of those we have are growing in containers on the driveway or around that area.
The day lilies are starting to bloom. These are descendants from some we dug up in the woods of Pennsylvania, near our property. They are growing around what used to be a homestead, many years ago. There is a hole in the ground with the remains of stone walls and the base of a chimney. Around that are orange day lilies (Hemerocallis fulva) and periwinkle (Vinca minor) growing in great profusion. It’s in the shade as trees have grown up over it and in consequence the day lilies don’t bloom as well as they might, but we took a few home and planted them in the sun, where they bloomed quite happily. That was at our old house and we dug up and brought some of those with us here, where they continue to give a great show every year.
I took a few more pictures of plants on Cathy’s work table today. This one is a spurge called Euphorbia amygdaloides subsp. robbiae, also known as Robb’s wood spurge. It’s a nice combination of greens and yellows and something nice for the herbaceous border. The Euphorbia genus has something like 2,000 species and they range from small annual plants to trees and there are species from many parts of the world This one isn’t native to North America, but I’m not bothered by that. One thing you want to be careful of with these plants is their milky sap, which is poisonous if ingested and a skin irritant.
The gooseberries (Ribes uva-crispa) are just about ripe. The squerrals are eating them as they ripen up and I don’t think we’re actually going to get much of a harvest. That’s our own fault, because we haven’t protected them and aren’t going out each morning to pick them as they ripen up. I don’t mind, terribly, although I have been picking and eating them when I do go out. They are just the right combination of sweet and tart. If I had a bit of land and used some of it for vegetable gardening, I think I’d plant a row of these and put a net over them. I might put a net over this one next year, although it’s against the fence and that might make it tricky.
Over the years I’ve thought about selling photos as stock but I never really got into it. I’m not really sure if I’d actually make any money at it. I sort of doubt it, honestly. I know that now and then I get a reasonably good photo and I certainly enjoy both taking and looking at them. But whether they are actually suitable for stock is another matter. And of course it isn’t just that. They would have to be found among the hundreds of thousands of other stock photos. I’m sure there are ways to increase your chances but I’m not sure I care enough. So, I’ll just stick to what I do and occasionally post a photo with an attempt at a clever title. This is stock, Matthiola incana.
The blackberry lily (Iris domestica, formerly known as Belamcanda chinensis, has beautiful, bright orange flowers above an attractive fan of sword-shaped leaves. It spreads slowly into clumps but mostly spreads by seed, which are distributed both by birds and by wives who really like it in our garden. I first collected seeds in South Carolina many, many years ago and we’ve had it around ever since. We have quite a few at this point and we may be reaching the time when a few of them need to be pulled up (but I’m not sure Cathy’s ready for that yet). They are native from the Himalayas to the Russian far east but do very well here. I like the lighting in this. The bloom is in full sun and the background is the pavement of our street in shadow.
This is the tip of a mullein stalk growing up close to the front of our house. It’s not really in a place I’d choose to plant it, but I left it there for Cathy. She really likes it and we have a fair amount in the hawthorn bed that has become something of a Mediterranean garden this year. It’s funny to hear so many people praise this plant as something the native Americans used medicinally. It may be true, but that only happened after it was introduced from Europe, as it isn’t a native American itself. It’s quite hardy (USDA Zones 3 to 9) and is quite happy in dry, otherwise barren places. This part of our yard really dries out in the summer and is currently rock hard. But along with the Verbascum we have Verbena bonariensis (tall verbena), Lavandula stoechas (Spanish lavender), and Salvia rosmarinus (rosemary), which all do well in rather severe conditions and in fact don’t like being waterlogged.
This won’t be the only photo I post of these, I suspect. They are starting to bloom and are already quite spectacular but when they really get into full bloom, with 20 or more flowers per stem, they are amazing. The seem to deal pretty well with the sweltering heat we’ve had and the occasional downpour. The biggest threat to them, actually, is deer, which will come in and eat them. We’ve been fortunate this year and only a few stems have been cut off (and that may be rabbits). We have them in a few places around the yard but the most conspicuous are in the front, right out near the road, where there used to be a large oak tree (until it died and the county cut it down).
It wasn’t so hot today, although relative humidity was near 100%. Cathy and I went out for a walk at the former Redgate Golf Course, now Redgate Park. We saw a pair of white-tailed deer (a mother and fawn) as well as a few different wildflowers. This is a pretty common one, an import from the old world, but still a pretty flower. The others that I photographed were also non-natives. There was the Asiatic dayflower (Commelia communis), which has two white petal-like structures above the flower, and moth mullein (Verbascum blattaria), a pretty, little, white flower with a magenta throat and stamens. We also went to Rockville Cemetery, where we saw another fawn, and then Croydon Nature Center before returning home.
Cathy and I went for a walk this evening. After yesterday’s rain it was cooler. Not quite cool enough to be really pleasant and still quite humid, but so much better than it’s been that we had to get out. There’s one place we walk by where the park comes right up to the road and I took this photo of common burdock (Arctium minus) along the edge of the woods. It’s a biennial native to Europe but pretty well established as a common weed here now. It has burrs that stick to fur and clothing, which helps it to spread.
Cathy has this hardy begonia (Begonia grandis) growing a few places around the house. It really seems to like the relatively shady area around our front door, which gets a little morning sun but that’s it. And even that is filtered through the foundation planting. It seems particularly happy this year, with the amount of rain we’ve had. It’s just coming into bloom, with its delicate and interestingly shaped, pink flowers. But I think it’s worth having just the leaves. We have a few little seedlings that Cathy has collected and she will try to get a few established in new places.
I had a picture of the leaves of this Hardy Begonia (Begonia grandis) earlier this month. Now it’s in bloom and adding a little brightness to the shady spot outside our front door. It’s a great plant to have and looks like it shouldn’t be sturdy enough to survive our winters but it does and it actually does quite well. It won’t grow well too far to our south because of the heat of summer or too far to the north because of the cold winters, but here it’s quite reliable. Highly recommended.
As a landscape plant, burning bush (Euonymus alatus) can be quite striking. I hesitate to ever recommend it. It is an invasive and its use is actively discouraged in many areas (and even banned in Massachusetts, I believe). It’s a native of northeastern Asia and is naturalized over much of eastern North America. The plant we have is in a pot, which helps keep it small, although I’m not really sure I want even that much in my yard. Not that getting rid of ours is going to make much difference, as this is grown all over our area and the cat is already out of the bag.
Cathy and I drove up to pick up our car from the shop this evening and then I stopped at the nature center on the way home to see if I could find anything worth photographing. I took a few nice pictures including a few of the berries of a Japanese barberry (Berberis thunbergii, also known as Thunberg’s barberry). This is an invasive species and I generally don’t recommend it. It’s somewhat too late to worry about, though, because it’s already everywhere. And of course there are hundreds of them at the garden center. They do may nice plantings, so I understand why people use them. Note that the fruit is edible and I have used it in a few Persian dishes. They have a great, tart flavor, similar to cranberries.
We’ve grown Torenia fournieri before but I don’t think it has ever done as well ad it did this year. We have a couple of them in containers on the back patio and they have been in constant bloom all summer and will probably not stop until we get a killing frost. They are also known a wishbone flower because the stamens join to form a shape similar to the wishbone of a chicken. This one is a variety called ‘Summer Wave’. Ours got a bit of sun but they are also really good for shade. You better believe we’re going to get this again next year.
Today’s walk was in Redgate Park, formerly Redgate Golf Course. We walked the back nine today and enjoyed the cool weather and saw quite a few birds, including some blue birds and a hawk that I got a pretty decent photo of as it took off from a branch. This is Japanese barberry (Berberis thunbergii), a widely naturalized alien plant that’s found throughout our woods. I know we aren’t suppose to like invasive, non-native plants but you have to admit, its fall colors are quite spectacular.
Dorothy, Cathy, and I walked on the Seneca Greenway Trail this afternoon, parking where MD 28 crosses Seneca Creek and walking downstream. We only saw a few other people and it was a very pleasant walk. It’s relatively flat, with only a few ups and downs to deal with. The birds were out in force and we heard them all around, although we weren’t stopping to see them so much and didn’t really get very close to any. I did stop to take a few photos, including of this fig buttercup, also known as lesser celandine. It was formerly classified as Ranunculus ficaria but is now Ficaria verna. It’s an invasive, non-native species that grows in many of our wetlands.
We were out at Rocklands this morning with Dorothy for their chick-rental pick-up. I took a walk at one point to take some pictures of Anna’s flowers. It was a wet, cool day and there isn’t a lot in bloom at the moment but the love-in-a-mist (Nigella damascena) was blooming. The flowers are a lovely shade of pale blue and I think it’s even prettier in the rain, with water droplets on the various flower parts. This is a very hardy annual, growing well up to USDA Hardiness Zone 2, although it’s only native to northern Africa and southern Europe.
A few weeks ago we went to Stadler’s with our friend Yvette to buy a few plants for her. She wanted to plant something in memory of her nephew and wanted something blue. She settled on a balloon flower (Platycodon grandiflorus), which is actually more blue to the eye than it appears here. It’s a really pretty perennial that should do well as long as it’s got the right amount of water. We bought one, too, and have it in a container outside our front door, greeting us with these big, sky blue flowers, and reminding us of Jack, as well. It’s native to the northern far-east and is quite hardy and easily grown. The only thing to watch out for is wet or poorly-drained soils (which is why growing it in a container is easier for us).
While not a native, common yarrow (Achillea millefolium) was introduced to North America in colonial times, and has since naturalized throughout the United States. It’s considered by some to be an invasive weed, although we’ve never had a lot of luck with it surviving in our garden. This specimen is a cultivar being grown in the Master Gardener’s demonstration garden at the Agricultural History Farm Park and it’s a lovely color. It certainly makes me interested in giving it another try. There are paler versions, as well and some really nice yellows. We have plenty of yellows, though, so I think I might go for something like this.
We had this in the past but haven’t had it since we moved here in 2006. Crocosmia ‘Lucifer’—a hybrid bred by Alan Bloom and officially Crocosmia x Curtonus—has wonderful, bright red flowers and we really should plant a large clump of this. As it is, we just have a single plant but maybe we could buy some more to add to this location. It’s growing in our large, front bed and clashes a little with the otherwise purple theme of the bed, but who can complain about such a red. The species of the Crocosmia genus are mostly native to the grasslands of South Africa.
We’ve talked off and on about getting a chastetree (Vitex agnus-castus). The question we haven’t answered yet is where we’d put it. I wouldn’t mind cutting down the holly that’s growing near the intersection of our front walk and driveway and putting it there, but so far, that’s just me. It would be a big change and for a little while it would make the area look comparatively empty. I think it’s worth it, frankly. I’m not a big fan of holly trees, especially when I’m outdoors barefoot and step on the leaves. Hollies are evergreen, of course, and the robins do like the berries in the winter, but those are the only real assets, as far as I’m concerned. The holly tree is a native plant, of course, but we’d have to change a lot if that was going to be a reason for growing something. It does bloom, it’s true, but the flowers are nothing compared to this. The Vitex flowers are small, but they are fragrant and are lavender to pale violet, attracting bees and butterflies in great abundance. I’m a fan of bees and butterflies.
The tiger lilies (Lilium lancifolium) are blooming. These were all descended from bulbils that we took from lilies growing at my parent’s house. We started with just a couple and the rest came from those. We have them in a few different places in the yard but this is the largest group of them. they stand over six feet tall and they are pretty noticeable. Each year the group gets just a little larger. Last year I collected seeds, as well, although we never did anything with them. I may scatter some on our property in Pennsylvania. They should do well there.
Cathy and I went for another walk after church today (that’s pretty common, as you might have noticed). This time we went to the Blue Mash Trail on Zion Road behind the Laytonsville land fill. I didn’t take many pictures and most of them were of Asiatic bittersweet (Celastrus orbiculatus) as in this photo. I particularly like this picture because of the added color of the juniper (most likely eastern red cedar, Juniperus virginiana). We have a native bittersweet (Celastrus scandens) but I’ll confess that I could not readily differentiate between the two, basically assuming that anything we see is the more aggressive C. orbiculatus.