Category Archives: Host Plants

Being a good host

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Butterflies getting nectar from Gregg’s mistflower

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.

The open blooms of the Compositae are the perfect landing stages for butterflies

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

Chinquapin oak leaf

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.

Live oaks

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.

Redbud buds in spring

Spring flowering Mexican Plum with Red Admiral

The well-known redbud (Cercis canadensis v. texana) and Mexican Plum (Prunus mexicana) host the larvae of Henry’s elfin butterfly and the Tiger Swallowtail respectively.

Big bluestem

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.

Tecoma stans

There are several flowering natives, readily available for landscaping, that serve as host plants for butterfly species.

Black Dalea

Tecoma stans and Black Dalea (Dalea frutescens) provide homes for the larvae of the Dogface butterfly.

Soft grey foliage and pink blossoms of Cenzio

The popular Cenzio (Leucophyllum frutescens) plays host to the larvae of the Theona checkerspot and the ubiquitous Lantana sp. offers

Lantana horrida

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.

Asclepias tuberosa (butterfly milkweed)

Asclepias asperula (green flowered milkweed)

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?

References:

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.

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Flowering phases II: Spring flowering Shrubs

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Yellow blooms of Agarita seen in February

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.

Flowers of Texas Persimmon

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.

Fading blooms of Eve’s Necklace

Seed pods of Eve’s necklace

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?

Lepidopteran Surprises!

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It was a spring for caterpillars, butterflies and moths in Texas.  But I was still surprised when I was walking to my car in May and saw clumps of caterpillars on the evergreen sumac in the parking lot.  Much to the joy of colleagues and students we watched the caterpillars devouring great sections of leaves.  What made it even more interesting was that while some of the caterpillars stayed in a tight group others had wondered off by themselves a little and would arch their backs if you peered too closely.

Curious, I contacted the LBJ Wildflower center and they put me in touch with a volunteer who was an expert in these matters.  Several emails later the caterpillar was identified as Datana perspicua or spotted Datana.  It turns out that they are the only species that uses Evergreen Sumac (Rhus virens) as a host plant and then they go underground before emerging again as an adult!