Host plants are just one part of building habitat into the landscape. In biology the term”host” frequently means the organism that a parasite lives off of. But in the context of landscape “host plant” refers to those species that support the larval stages of butterflies and moths. When you imagine a butterfly garden, you might be inclined to think of beautiful borders full of purple, blue, white, yellow and orange blooms.
Open blooms, with bright color and little scent are the classic butterfly attractors. But these are the nectar plants that sustain the adult butterflies.The larvae frequently need a different suite of species to develop.It is surprising to find that a number of grasses and trees are important as host plants. It is also encouraging to discover that a number of species common in the landscape or easily available are equally important to a number of butterfly species.
Juniperus ashei (cedar), the bane of allergy sufferers, is important in the life cycle of the Olive and Juniper Hairstreak butterflies, as well as providing nesting material for the Golden cheeked warbler and berries for a variety of birds. Several of the oaks (e.g. Blackjack, Post Oak, Shumard oak) also play host to specific species, for example the Chinquapin oak (Quercus muehlenbergii) feeds Horace’s Duskywing butterflies and provides acorns for squirrels and birds.
Quercus virginiana (Southern live oak), that graces many landscapes in Austin, is simultaneously providing home to small mammals and songbirds while providing sustenance for Horace’s Duskywing and the Northern White M hairstreak butterflies.
A variety of Skipper butterflies (see identification of butterflies and moths of north america) utilize different grasses as larval host plants. Common prairie grasses such as little bluestem (Schizachyrium scoparium), Big bluestem (Andropogon gerardi) and Switch grass (Panicum virgatum) play host to different species belonging to this family of butterflies that comprises approximately 1/3 of all North American butterfly species. Inland sea oats (Chasmanthium latifolium) is a native commonly used in landscaping that also hosts multiple species of these stout, small winged, fast flying butterflies.
There are several flowering natives, readily available for landscaping, that serve as host plants for butterfly species.
Tecoma stans and Black Dalea (Dalea frutescens) provide homes for the larvae of the Dogface butterfly.
The popular Cenzio (Leucophyllum frutescens) plays host to the larvae of the Theona checkerspot and the ubiquitous Lantana sp. offers
nursery sites for the Painted lady larvae.
There are climbers that are favored by particular butterfly species Old man’s beard (Clematis drummondii) is dramatically covered with feathery achenes in the fall, sustaining birds with their seeds. In spring their leaves feed the larvae of the Fatal metalmark butterfly. The different species of passionflower vines are renowned for hosting a wide variety of butterfly species including many of the Fritillaries.
Finally it would be remiss if we did not mention the special relationship that the most famous of Texas butterflies, the endangered Monarch, has with the milkweeds . The toxins in the sap of the milkweed family are processed by the larvae making them toxic as well. This poisonous state is carried through metamorphosis into adulthood making them distasteful to birds that might prey on them.
Texas’ position at the base of the North American continent, places it in a position where it is the funnel that many migrating species (such as butterflies and birds) pass through. Thus, we have the delight of the aerial show of butterflies that pass through in Spring and Fall, as we as those that brave the hot summer and vagaries of winter. With a little forethought and planning we can be good hosts, planting species that provide sustenance for the young and old as well as shelter from wind, sun and rain.
Do you have any novel ideas for providing for wildlife in general, or butterflies in particular? Perhaps not just in residential landscapes but larger scale areas associated with business or local parks?
Noreen Damude and Kelly Conrad Bender (1999). Texas Wildscapes: Gardening for Wildlife. Texas Parks and Wildlife Press.
Jim P Brock and Kenn Kaufman. (2003). Field Guide to Butterflies of North America. Houghton Mifflin Company.
A member of the Pedaliaceae that is also known as Ram’s Horn for it’s fantastic seed pods.
Can’t tell you how pleased I am that this plant, which has popped up in the greenbelt behiind the fence, is a native rather than an exotic or invasive. According to Enquist, this is an occasional plant of roadsides and wastes., common only in Mason County. The seeds apparently attach themselves to bypassing animals, thus spreading and propagating the species. Apparently the seed pods were used for food by various native tribes of the Southwest, as well as plant fibers which were used for weaving. The plant has a rather strong unpleasant odor, which means that the photograph is more pleasant than the taking of the photograph. Ajilvsgi recommends it for the xeriscape garden, if there is room. It blooms from June to September, usually only a few flowers at a time.
A quick look at fascinating, if not friendly, beetles on a common native aster.
There is something joyous about a field of flowers. When nature repeats with reliability, like the appearance of the bluebonnets, it penetrates through the layers of our lives that separate us from our natural surroundings. Not only do we reconnect to seasons through plants, but it also serves as a subtle measure of the health of the ecosystem. Note all the news reports on wildflower predictions each year.
What is perhaps just as remarkable, but less remarked on, is the subsequent unfolding of flowers, annuals and biennials, through the spring. The Bluebonnets (Lupinus texensis) are among the first to appear with the occasional patch of Indian paintbrush (Castilleja coccinea) to highlight the colors tastefully.
What follows is the sequential flowering of different species. Many from the Asteraceae and while some, like scrambled eggs (Corydalis curvisiliqua) are from more obscure families like Fumariaceae. Together they form layers in the landscape in space and time. The casual manner in which the form and color of these species, frequently seen on roadsides, complement each other always strikes me as rather amusing given the effort and time someone might put in to create the same, very temporary effect. Eventually the fields of blooms give way to smaller and smaller patches until finally we arrive at the enormous sunflowers of the summer.
The ever changing mosaic of these roadside species is largely connected to environmental conditions and germination requirements. Some seeds, like those of the bluebonnets require stratification and fall rains for the plants to germinate and begin growing well before Christmas. Similarly, the firewheel (Gaillardia pulchella) seen here with brown eyed susans (Rudbeckia hirta) should be planted early as they require 70F to germinate and so may only appear the following spring if the weather warms up too quickly.
While the annuals and biennials are tied to seasons through seed germination. It is possible that perennials might offer more reliable color, although their flowering (timing and profuseness) is tied to weather conditions as well.
Primrose is a common name applied to members of the genus Calylophys sp. and Oenothera sp, both found in the Onagraceae. These species provide alternate yellows to the early daisies and occasionally delicate pink.
The purple/blue range of the spectrum can be found in the wine cup (Callirhoe digitata). A perennial with a deep tap-root, it has leaves close to the ground year round, but sends dramatic purple flowers up over grasses and neighbouring plants early in the spring. A more upright form is that of Widow’s tears (Commelina erecta) which, while
low (growing about 1-3 ft tall), offers a vertical line in contrast to the Purple prairie verbena (Glandularia bipinnatifida) that grows profusely with a relaxed habit that is frequently covered with butterflies.
Hummingbirds find a food source in the bright red cedar sage (Salvia roemeriana). With it’s attractive leaf it brightens shady spots from early spring until mid summer, providing dramatic contrast to the white caliche stone and brown mulch found in forested areas.
Spring in Texas clearly offers a diverse palette of color and form. To mimic the natural sequence and arrangement of wildflowers one must understand both germination and flowering requirements of the plants selected. Like a puppet master it is all in the timing of seed application, watering and of course placing of both perennials and the annuals/biennials. Can you imagine selecting 4 or 5 species to place in an area for a spring show? Can you imagine a “meadow” effect in say a 3×3 ft area? What are the important criteria that we can take from nature to implement in design in order to attain that effortless look of sequential color?
Like trees, shrubs are appealing not only for their attractive flowers, but also for their permanence in the landscape and the possible offering of food in the fall. Thus, while it is interesting to note those early bloomers, that help to wake up the landscape and our senses, paying attention to leaf shape and architecture can add a subtle dimension to landscape. Walking around the back paths of the LBJ Wildflower center early one spring I smelt the most delightful sweet scent. It was particularly elusive but, following my nose for a bit, I was able to trace it to the Agarita bushes. It surprised me that such a delicate smell game from the strings of small yellow blooms as the bush itself is incredibly robust and the leaves are uncomfortably prickly, just like a holly’s. In fact it is known to be selected by birds for nest sites as the dense prickly foliage offers excellent protection. As the picture indicates the ephemeral yellow blossoms result in bright red berries later in the year.
Diospyros texana is a wiry looking shrub. It offers a great sculptural element to the landscape heightened by its beautiful bark. In the spring it has delicate little bell-shaped flowers that produce fruit later in the summer. The small fleshy fruits of this hardy tree provide food for birds and small mammals.
In the woodland, surprisingly tropical looking blooms hang overhead. Eve’s necklace (Styphnolobium affine) offers graceful stems, delicate pink yellow blooms clustered on dangling infloresences and vibrant green compound leaves that move easily in the breeze. While it is a very attractive, it should be notes that the black seed pods house toxic seeds. Similarly it’s close cousin the evergreen Texas Mountain Laurel (Sophora secundiflora) has very attractive blooms that have a sweet scent, particularly evident in the evening, that give rise to silvery seed pods housing toxic red seeds. This is a very popular landscape tree, although it is slow growing, and this year the flowering in February and March was remarkable! This may be connected in some way with the drought/spring rain weather patterns that we experienced.Part of the delight of a Texas spring is the advent of the rains and the filling of the creeks. Here along Bear creek, a contributor to the Edwards aquifer, we find Button bush (Cephalanthus occidentalis). This versatile shrub is particularly useful in riverine areas. It does not mind having it’s roots regularly or partially submerged and it offers both nectar to insects and seeds to ducks and rodents. The glossy green leaves present a third leaf type to consider, the entire leaf.
Our introduction to these species presents us with further considerations for the landscape. We had already met the idea of host plants (with Agarita and Texas persimmon), but now we introduce the possibilities of evoking interaction through the senses, smell and sight. Scents can be intriguing and invite exploration while different leaf shapes offer visual interest. Can you suggest particular arrangements or collections of shrubs? How do they meet with your selection criteria?
Moving into Fall it is hard to remember the possibilities of spring. Creating a landscape with staggered flowerings is aesthetically interesting and serves to mark the passage of time. Those early spring blooms cheer us as much as the watery sunbeams peeking through grey clouds, but they also have an important ecological function in providing a continuous food source for those species that utilize pollen and nectar. So now, as the heat of summer burns away all memories of cooler weather, lets consider some of the early spring bloomers.
The Crabapple (Malus ioensis)
seen here blooming out near Johnson city in February is perhaps one of the earliest. Deer are very fond of this tree and so they do have to be protected from browsing.
Small bitter fruits will follow in early fall.
Texas has several native trees that are early bloomers. Some like the redbud and Mexican plum have very obvious blooms that are enjoyed by humans and pollinators alike.
These are well-known trees for landscape and pair well together visually and in terms of flowering time. Mexican Plum has the added attractions of plum-like fruit and fall color in later seasons, while Redbud’s offer interesting leaf shape and large pods.
Mexican Buckeye (Ungnadia speciosa) is equally attractive mid-size tree or large shrub that has early flowers
and very interesting seed pods later.
The Mexican buckeye is not actually a true buckeye. The Red Buckeye (which is a true buckeye) has a similar common name but belongs to a different genus and species – Aesculus pavia. The images of the flowers were taken in March on a hike down to Hamilton Pool.
Not all blooms follow the traditional flower form of petals, stamens, stigma, style and ovary. Huisache (Acacia farnesiana) combines flowers in clusters with the yellow filaments of the stamens producing the attractive color.
Pods 3 -4 in long soon follow. The light green compound leaves are very attractive, however the tree is thorny and readily sheds small twigs. Combined with the fact that a dark blue-brown color leaches from the pods when they are wet, this might not be the best tree for a patio or walkway but it is delightful set in a parkland.
The oaks are another group of trees with flowers that may not immediately be recognized as such.
The catkins are a collection of flowers (inflorescence) just as the yellow balls of the Huisache are. The male and female catkins of the Spanish Oak (Quercus buckleyi) have a slight pinkish tint just like the new leaves. The flowers on the male catkins produce pollen and then fall away while the fertilized female flowers of female catkins produce the acorns that we are familiar with.
These are a small sample of early flowering trees. They may be selected for their flowers, or for other characteristics such as leaf shape, autumnal color, food source or animal habitat. How would you rate selection criteria for trees? Do you have particular features that continue to frame decisions time and time again? How important is flowering time to you?
Milkweed is a wonderful, and essential, host for the Monarch butterfly. However, these pictures beautifully illustrate the complexities of the food web with a milkweed at it’s heart.
When considering plants in a landscape there is often an emphasis on using local or native species. Ignoring the all important “What constitutes a native species?” . The next consideration is “Why use native plants?”. This is hardly a new question in the world of landscape design. But there is a persistent myth that using native plants in landscape makes things easier and less costly. That statement invites an interesting debate which points to the fundamental requirement for knowledge about plants and their interaction with the environment. Planting anything without insight into the basic biology and ecology of a plant is playing “landscape roulette”. It is also necessary to have both macro- and micro- understanding of an area
Fortunately this is relatively easy to achieve given the growing body of knowledge of plant eco-physiology and the fact that ecological patterns appear like repeating fractals at different scales.
Take for instance the standard world biomes map we see patterns connected to climate and vegetation. It is not surprising that if we look at a map of the Texas “ Natural Regions” or “Ecoregions” we see similar patterns of vegetation connected to topography, rainfall and temperature.
Thus, learning to “read” the landscape is as important as getting to know the foibles of the local “characters” – the plants.
And we still need to answer why “locals” should get preference.
In nature where a plant is seen to grow is the result of a history of seed dispersal, germination conditions and physiology.
In a constructed landscape where a plant grows is the result of someone’s intent and care – and the physiology and biology of the plant.
Knowledge and experience of the plants, climate, ecology and landscape purpose are fundamental to success in a situation that is largely bound by the laws of nature.
So what is important in considering conditions for creating landscape are those same things that define broader picture of natural plant dispersal – rainfall and temperature, topography and soil. [Useful documents like the soil types of Texas, describe in great detail local conditions – to the point of being overwhelming]. But these environmental variables are usually far from static, or predictable, and it is not necessarily the averages which define a plant’s distribution. More often it is the extremes.
Consider the climate in Austin. If you view the averages it appears to be a pleasantly warm climate, view the extremes and it is possible that a plant has to deal with freezing temperatures and days of 100+F in the same year, not to mention winds, excessive rain or no rain at all.
We are all very aware of the growing challenges associated with rainfall. Last year presented Texas with its worst drought in many years (US total precipitation 2011), and there does appear to be a shift in rainfall totals over the past decades (changing US rainfall since 1960).
It is not only rainfall that is shifting. The USDA has recently published a new plant hardiness map minimum temperatures that reflects changes in climate. There is finally recognition that the hottest temperatures challenge plants as well and the American Horticultural Society has produced a heat zone map.
Perhaps the most hidden, or least considered factor, is how land is actually being used. A new vision that considers human land use in an ecological context makes the world biomes map we are familiar with seem grossly oversimplified. Anthropogenic biomes and the impact of human land use at a local level highlight the importance of intelligent and ecologically informed decisions with regard to landscape, particularly in the urban setting. This picture of the less than pristine biome, ever-changing land use, and pressure on fundamental natural resources, such as water, should lead us to expand the role of plants in the intelligently constructed landscape. Plants are the ecological go-between, the mediator between static urban structure and capricious natural events and forces.
Now having considered our landscape, we can return to the questions “why use native species?” and “what constitutes a native species?”. Situated in context of the immediate environment the conversation may be less academic.