Breaking the winter fast

Posted on March 19, 2014 by botanyfordesign

Blanco crab apple at Selah Bamberger Ranch

It’s been a curiously cold winter here in Texas, while elsewhere in the country has been inundated by unrelenting snow storms. Still the first Spring trees are beginning to flower and the crab apples have been blooming for almost three weeks despite the weather alternating between freezing temperatures as low as 28F and highs near the 80’s. Here the Blanco crabapple (Malus ioensis var. texana), an endemic species of the Texas Hill Country, is blooming next to a tributary of Miller Creek on the Bamberger ranch. This splendid tree is a member of the Rosaceae family and, as it’s genus (Malus) suggests related to the domesticated apple. The characters that place this plant in the Rosaceae family are best seen in its flowers. The blooms are actinomorphic, meaning they are radially symmetrical. They have five petals, as can be seen in the adjacent close up, and five sepals. The flowers have both male and female parts, making them hermaphroditic, and many stamens arranged in whorls. Three stigma and styles (slightly greenish structures at the center of the flower) are evident in this photograph

Close up of the Crab apple flower by Abe Halbreich

disappearing into the top of the ovary that will ultimately become the apple once the flowers have been pollinated. The base of the flower, calyx (sepals), corolla (petals) and androecium (filaments of the stamens) essentially fuse to form a hypanthium enclosing the ovary. According to the Ladybird Johnson site, this species is particularly important to a variety of native bees. Naturally the bitter fruit that appear later in the summer are food for a variety of animals. As a harbinger of spring and warmer weather it brightens the dry, cold landscape and it’s bright fresh blooms easily draw the eye against the brown palette of the grasses and olive green cedars.

Lake Madrone at the Bamberger Ranch in February 2014

Texas Mountain Laurel – Sophora secundiflora

Posted on March 13, 2013 by botanyfordesign

Spring is springing up quickly after our warmish winter. The mountain laurels have been blooming for over a month now and are slowly beginning to fade. Their bumpy seed pods, containing poisonous seeds, are appearing from the delicate purple-blue blooms that still fill the night with heady scent. I thought it might be fun to take a closer look at these flowers since this species is a member of the Fabaceae, one of the largest and most cosmopolitan of all plant groups. Just about anywhere in the world you will find examples of the pea family. They could be evergreen, deciduous, climbers, herbaceous plants or trees. Specifically, Texas Mountain Laurel is a beautiful evergreen multi-trunked trees that is part of the sub-family Faboideae. This is the group of Fabaceae that we typically recognize as “pea”. The other two subfamilies are Mimosoidae and Caesalpiniodae.

Half flower diagram of Texas Mountain Laurel

So what is a “classic” pea flower. It has a floral structure where the petals are arranged into banner, wings and keel.

Stigma, style and ovary of the Texas mountain laurel

The banner is one large petal with two wing petals enclosing two keel petals. The keel closes around the 10 stamens and the ovary that will later develop into the pod if the flower is pollinated. Two curious features of the flower are the widening of the filaments at the base (filaments support the anther forming the stamen) and a protrusion on the lower side of the keel petal which seem to help the petals stay closed over the stamens and stigma.

10 stamens clustered tightly around the gynoecium

What’s green in January? #1

Posted on January 28, 2013 by botanyfordesign

This past Sunday I took a drive out into the hill country. I was visiting one of my favorite places – the Bamberger Ranch. While there are green trees (Live oaks – Quercus fusiformis and cedars – Juniperus asheii) scattered through the landscape there were many without any leaves. Yet they still had what appeared to be balls of greenness high up in their canopy. These apparently innocuous tufts of green are actually parasites (mistletoe –Phoradenron tomentosum) with their haustoria deep in the xylem and phloem of the plant they draw out the nutrients from the very heart of each branch. The leafy parts seen here are growing out of a small Spanish Oak (Quercus texana). The texture of the leaves is leathery and quite tough. What is not seen here are the tiny white berries that the birds love to eat. We are perhaps more familiar with the idea of red berries on mistletoe since that is what is found on the european mistletoe Viscum album. When the berries pass through the gut of the bird they become goeey and the bird has to wipe its bottom on a branch to remove the dropping. In this way the berry becomes attached to the next victim, commonly Cedar elms (Ulmus crassifolia) or hackberry (Celtis laevigata), and the haustoria (specially adapted roots) can grow into the bark and a new plant is infected. Amazingly haustoria can extend deep into the plant. After removing an infected branch from a Spanish oak I traced haustoria up to 2 yards inside the vessels of the plant! I do wonder if trees are more prone to infection with all the droughts we have been having. I seem to be noticing it more and more each winter and infected trees seem to have more infestations. Do plants typically have resistance to parasites and that is weakend by drought?

Fall Color

Posted on December 2, 2012 by botanyfordesign

cedar elm (Ulmus crassifolia)

While many parts of the country have begun their winter, here in Texas we are still enjoying the balmy days of Autumn. While our fall color isn’t perhaps as dramatic as some places in the country we still have some lovely yellows and reds set against the backdrop of the evergreen cedar. (Juniperus ashei). Cedar elms are tall stately trees that can be found on their own or hidden within the forest. This year their small winged fruits covered the ground in September and October as their yellow golden leaves are doing now.

Bur oak (Quercus macrocarpa)

Another source for hints of gold on the hillside is the Bur Oak. The leaves of this oak are enormous as are their beautiful acorns that have caps with dramatic “burrs” surrounding them. A beautiful tree in a park setting this wonderful tree is now dropping its leaves, that are the size of a childs shoe, making a crunchy brown flooring for park goers to enjoy in the fall light.

Spanish Oak (Quercus buckleyi or texana)

Oaks are also a source of dramatic reds seen along roads and on hillsides. The Spanish Oak belongs to the group of Oaks known as the Red Oaks and doesn’t disappoint. The identification of this fast growing species can be tricky as it has much in common with the Shumard Oak (Quercus shumardii) and Southern Red Oak (Quercus falcata). Another source of deep red is from a slightly small tree, the flame leaf sumac (Rhus lanceolata). This wonderful plant specimen changes from a vibrant green in the spring to a deep red in the fall. It candelabra like inflorescences of tiny cream flowers resulting in reddish seeds which marks the beginning of the change in late September/October. Their color emphasized by the late fall light they optimize winter metaphor of burning the old and opening ways for new beginnings.

flameleafsumac

Spring flowers III- Color wheel cycle

Posted on September 10, 2012 by botanyfordesign

bluebonnet

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.

indian paintbrush

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.

bluebonnets and indian paintbrushes

scrambled eggs growing in a naive lawn

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.

brown eyed susans (all yellow) together with firewheels (orange and yellos)

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.

Missouri primrose (Oenothera macrocarpa

pink evening primrose (Oenothera speciosa)

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.

wine cup

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

Widow’s tears

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.

Purple Prairie verbena

cedar sage

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?

Flowering phases II: Spring flowering Shrubs

Posted on September 5, 2012 by botanyfordesign

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?

Flowering phases I: spring flowering trees

Posted on September 4, 2012 by botanyfordesign

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.

Crabapple blooming in February

Small bitter fruits will follow in early fall.

Redbuds seen in a spring landscape

Redbud blooming in February

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.

Red Admiral on a Mexican Plum Blossom

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

Flower of Mexican Buckeye

and very interesting seed pods later.

Fruit of Mexican Buckeye

Red buckeye, note the classic buckeye type leaf

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.

Huisache blooms in May

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.

Catkin and new leaves of the Spanish oak

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?

Considering Native Plants

Posted on August 29, 2012 by botanyfordesign

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

Hawaii Savannah on Lava

Texas Savannah on Limestone

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.

Fire senescent Protea sp. in South Africa

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.

Mammilaria cactus, Texas

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.

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