Woodland Flora of Southeast America

Nicola Starkey, April 2014

Contents

TABLE OF FIGURES 2

ACKNOWLEDGEMENTS 4

ABSTRACT 5

INTRODUCTION 6

ROUTE 7

ATLANTA BOTANICAL GARDEN 8

HUNTSVILLE BOTANICAL GARDEN, 11

SPECIES ENCOUNTERED 13 CLOUDLAND CANYON, CUMBERLAND PLATEAU 13 SHIRLEY MILLER WILDFLOWER TRAIL, POCKET ON PIGEON MOUNTAIN 16 GREAT SMOKY MOUNTAINS 18

RECOMMENDATIONS 30

EXPENSES 31

REFERENCES 32

1

Table of Figures

Cover Picture: grandiflorum

Figure 1 Maps showing the route taken...... 7 Figure 2 A sculpture being prepared for bedding ...... 9 Figure 3 Snake sculpture...... 9 Figure 4 New Caledonian conifers...... 9 Figure 5 Carnivorous plants growing in the nursery ...... 10 Figure 6 The wetland garden at Atlanta Botanical Garden ...... 10 Figure 7 Interpretation about Wetland restoration...... 10 Figure 8 Habitat destruction under a pylon at Panther Creek, Georgia ...... 11 Figure 9 Harold and his cold frames ...... 12 Figure 10 Trays of trillium seedlings...... 12 Figure 11 The woodland area in Huntsville Botanical Garden ...... 12 Figure 12 At the top of Lookout Mountain on the Cumberland Plateau ...... 13 Figure 13 T. sulcatum at Cloudland Canyon ...... 14 Figure 14 The recurved petals of T. sulcatum ...... 14 Figure 15 T. cuneatum at Cloudland Canyon ...... 14 Figure 16 T .decumbens almost hidden amongst the leaf litter...... 15 Figure 17 Detail of T. decumbens ...... 15 Figure 18 Podophyllum peltatum covering an opening along the trail ...... 15 Figure 19 Podophyllum flower detail ...... 15 Figure 20 Prosartes lanuginosa ...... 16 Figure 21 Anemonella thalictroides ...... 16 Figure 22 Stellaria pubera ...... 16 Figure 23 Iris cristata (right)...... 17 Figure 24 Mertensia virginica ...... 17 Figure 25 T. flexipes along the Shirley Miller Wildflower Trail ...... 17 Figure 26 Actaea pachypoda growing in the same area ...... 17 Figure 27 T. felixipes growing with the yellow celandine poppy and Virginian bluebell...... 18 Figure 28 Detail of T. flexipes ...... 18 Figure 29 T. grandiflorum on mass ...... 19 Figure 30 T. grandiflorum with Phacelia fimbriata ...... 19 Figure 31 Detail of Phacelia fimbriata ...... 19 Figure 32 & Figure 33 Pollination of T. grandiflorum ...... 20 Figure 34 The pink flush as T. grandiflorum goes over ...... 20 Figure 35 T. erectum ...... 21 Figure 36 T. simile ...... 21 Figure 37 T. erectum with an extra petal, and one less anther ...... 22 Figure 38 Growing in the acid soils with T. erectum was a great swathe of Erythronium americanum ...... 22 Figure 39 Sanguinaria canadensis along the same trail, Kanati Fork ...... 22 Figure 40 Galearis spectabilis at White Sinks ...... 23 Figure 41 The floral carpet at White Oak Sinks ...... 23 2

Figure 42 T. luteum with Phacelia fimbriata ...... 24 Figure 43 T. luteum with Dodecatheon meadia, Podophyllum peltatum, and Phlox divaricata ...... 24 Figure 44 Detail of Phlox divaricata ...... 24 Figure 45 Detail of Dodecatheon meadia ...... 24 Figure 46 T. luteum with the red Silene virginica on the Chestnut Top Trail ...... 25 Figure 47 Silene virginica, only seen at two locations in the mountains ...... 25 Figure 48 The painted trillium, T. undulatum ...... 26 Figure 49 The pollinator gives an indication of the small size of this trillium ...... 26 Figure 50 T. catesbaei with distinctive recurved petals, and long anthers ...... 26 Figure 51 T. catesbaei growing through the leaf litter ...... 26 Figure 52 Pink form of T. catesbaei ...... 27 Figure 53 A grand , growing with T. luteum ...... 27 Figure 54 The pink and purple anthers of T. rugelii ...... 27 Figure 55 An unusual form with pale anthers ...... 28 Figure 56 Tom Patrick giving a tour on the Spring Wildflower Pilgrimage ...... 28 Figure 57 Tom pointed out this unusual form of T. luteum ...... 29 Figure 58 Tom took showed the group this hybrid of T. flexipes and T. erectum 29

3

Acknowledgements

I would like to thank the Merlin Trust and the Hardy Society for providing the funding for this trip.

I would like to thank the following people for their advice in the organising of the trip -

Aimee-Beth Browning Horticulturalist, RHS Harlow Carr

George Carl Denton U.K. National Collection Holder of Trillium

Tom Patrick Botanist, Georgia Department of Natural Resources, Georgia

Jenny Cruse-Sanders Vice President for Science and Conservation, Atlanta Botanical Garden

Ken McFarland Chairperson, Annual Spring Wildflower Pilgrimage

And to the following people for their time during the trip -

Ron Determann Conservatory & Conservation Director, Atlanta Botanical Garden

Harold Holmes Trillium Researcher, Harold Holmes Trillium Garden, Huntsville Botanical Garden, Alabama

Gary Walker Cliff-face Geologist, Appalachian University, USA

Also -

Adam Bowley Supervisor, Hardy Ornamental, RBG Kew

Joanne Everson Rock and Woodland Team Leader, Hardy Display, RBG Kew

Richard Wilford Collections Manager and Interim Head of Section Hardy Display Section, Horticulture, RBG Kew

4

Abstract

This report begins with an account of a visit to Atlanta Botanical Garden, followed by an account of a visit to Huntsville Botanical Garden in Alabama. The report then looks each of the that were encountered whilst hiking in the northwest of Georgia, and the Great Smoky Mountains, with notes on their habitat, where they were seen, and what they were growing with, so that this may be replicated in woodland displays in the UK.

5

Introduction

This study tour involved visiting the southeastern states of America in order to explore woodland habitats, and see the species rich plant communities of the Southern Appalachian mountain range.

The main aim was to learn which plants are found growing in the Southern Appalachians, and to see which plants are found growing together, in order to be able to replicate these communities in cultivated woodland displays. Different growing conditions would be noted to assist in growing these plants successfully.

The second aim was to study the genus Trillium, by familiarising myself with more species, improving identification skills of both these and other woodland perennials. This would be achieved by initially visiting Huntsville Botanical Garden to see trilliums in cultivation, and by hiking in the Cumberland Plateau, at Cloudland Canyon and Pocket on Pigeon Mountain, and in the Great Smoky Mountains.

Another aim was to learn about the micropropagation techniques used to grow trilliums at Atlanta Botanical Garden, unfortunately this wasn’t achieved, however a guided tour of Atlanta Botanical Garden was given, with an insight into conservation issues in the States, and the restoration ecology work with the genus Sarracenia.

6

Route

Figure 1 Maps showing the route taken

(Source: Google Maps)

7

Atlanta Botanical Garden

Ron Determann, the Conservatory & Conservation Director, gave a tour of Atlanta Botanical Garden. The 30-acre garden sits in Midtown Atlanta and was founded in 1976. The garden has a tropical house, where rare conifers from New Caledonia are housed, an orchid house, that was very similar in parts to the Prince of Wales Conservatory at Kew, during the Orchid Festival, and large outdoor sculptures that get planted up with bedding, which was reminiscent of Mainau in Germany.

The garden is heavily involved in ecology restoration, and grows plants for this purpose. Ron and his team were preparing Sarracenia plants, grown at the garden, to be transplanted in Florida the following day. The habitat of Sarracenia is under threat, mainly due to development in Florida, with it being a popular destination.

Ron also explained that woodland flora is under threat from herbicide run-off from agriculture, and that plants are sprayed off underneath pylons so that the vegetation does not have to be mown under them. This again leads to run-off. This was witnessed at Panther Creek, and the area was surprisingly large.

In America many people own land, rather than having gardens, so the land becomes private. This makes it difficult to monitor populations of plants, or save plants if under threat. Botanic gardens can approach landowners to ask them to conserve plants on their land, if they know they are there, but there are no laws that have to be abided to, and the landowner can do as they please.

This was quite an eye opener, having never travelled in the States before, and the enormity of conservation was a sobering thought.

8

Figure 2 A sculpture being prepared for bedding plants

Figure 3 Snake sculpture.

The garden contains a number of sculptures that will be filled with bedding plants for a colourful display.

Figure 4 New Caledonian conifers.

As part of the Conifer Conservation Group the garden houses a number of conifers in the Fuqua Conservatory. Ron believes that in order to preserve genetic material it should be shared amongst many locations, as an insurance against loses.

9

Figure 5 Carnivorous plants growing in the nursery.

The garden also has a number of Sarracenia that they rescued from an area that was under development

Figure 6 The wetland garden at Atlanta Botanical Garden

Figure 7 Interpretation about Wetland restoration.

10

Figure 8 Habitat destruction under a pylon at Panther Creek, Georgia

Huntsville Botanical Garden, Alabama

Nestled within Huntsville Botanical Garden is Holmes Trillium Garden, with over 30 species of trillium from both the east and west coasts of America, and including many cultivars. In 2006 Harold Holmes, and his wife Brenda, approached the garden to request permission to research trilliums, and to create a native woodland garden within the grounds. Fortunately Huntsville Botanical Garden agreed, and the two have created a beautiful corner of the garden, along with a number of polytunnels and potting shed.

Harold, an avid enthusiast, has trialled methods for successful germination and best growing methods, of both Trillium and Hexastylis. He sows trillium seeds fresh in trays, leaving them for a year after which he transfers the seedlings into a pot, where they remain for a further year or two, and then transplants them into the garden in clumps. The substrate he uses is bark/sand/perlite/professional mix compost with Epsom Salts, and fungicide.

A visit to this garden served as a great starting point to what would be seen in the mountains, as with everything labelled it meant identification was going to be easier.

11

Figure 9 Harold and his cold frames .

(Photo: Adam Bowley)

Figure 10 Trays of trillium seedlings.

Figure 11 The woodland area in Huntsville Botanical Garden.

Working voluntarily, Harold and Brenda have produced a beautiful and educational part of the garden. They have saved a population of Trillium flexipes from development by lifting it and bringing it here.

12

Species encountered

An aim of this trip was to become familiar with more species of trillium, in order to get to know the genus better. Eleven different species were identified. Seeing them in the wild also gave a clear understanding of the difficulties in , with hybrids encountered frequently. Unusual forms were seen, some with four petals, others with numerous sepals. Different pollinators were witnessed, but all were found not far from watercourses, often on sloping ground, coming through an extremely thick layer of leaf litter.

Cloudland Canyon, Cumberland Plateau

Trillum sulcatum was the first trillium to be seen in its natural habitat, at Cloudland Canyon, in the Cumberland Plateau. The Cumberland Plateau sits at the bottom of the Appalachian Mountains, making this a very ‘southern’ species, not found further north in the Great Smoky Mountains. The striking red T.sulcatum was growing individually and in small groups in the shade of a north-facing slope in the valley floor of the canyon, with a thin canopy of Tsuga canadensis. The Cumberland Plateau consists of sandstone with acidic soil, but the valleys that intersect it are limestone, weathering to neutralise the soil. The vegetation in this area is described as Mesic Forest, where there is a balance of moisture; not too wet, and not too dry.

Figure 12 At the top of Lookout Mountain on the Cumberland Plateau

13

Figure 13 T. sulcatum at Cloudland Canyon Figure 14 The recurved petals of T. sulcatum

The boat-shaped tips of the petals and sepals, as well as the dark maroon colour help to identify this species.

Further along Sitton’s Gulch Trail, in Cloudland Canyon, Trillum cuneatum was growing. This sessile trillium grew sparsely here, as individuals, or in groups of two or three. Preferring the conditions was Trillium decumbens. This trillium was hard to spot at first, as it lies flat on the ground, almost covered by the leaf litter, but once one was seen, the eye was drawn across the ground and suddenly a whole colony emerged through the leaves.

Figure 15 T. cuneatum at Cloudland Canyon

This is the largest of the eastern sessile trilliums with a vast range, and many forms.

14

Figure 16 T .decumbens almost hidden amongst the leaf litter.

Figure 17 Detail of T. decumbens

As the trail along the gorge valley began to rise, flatten out, and become more open, an expanse of Podophyllum peltatum covered the ground. T. decumbens found it’s through this colony. Previously unaware that Podophyllum grew on mass like this, it was wonderful to see.

Figure 18 Podophyllum peltatum covering an opening along the trail

Figure 19 Podophyllum flower detail

15

Other plants grew along the gorge valley, but mostly not in abundance, just small scatterings. All of these were seen again throughout the trip -

Anemonella thalictroides Arisaema triphyllum Phacelia bipinnatifida Calycanthus floridus Phlox divaricata Caulophyllum thalictroides Prosartes lanuginosa Cardamine diphylla Quercus sp. Erythronium umbilicatum Stellaria pubera Geranium maculatum Viola hastata Iris cristata

Figure 20 Prosartes lanuginosa

Figure 21 Anemonella thalictroide s (right)

Figure 22 Stellaria pubera

Shirley Miller Wildflower Trail, Pocket on Pigeon Mountain

A boardwalk has been built at the Shirley Miller trail at Pocket on Pigeon Mountain to protect the abundance of wildflowers that grow

16

there. This area is also part of the Cumberland Plateau in northwest Georgia. Amongst Mertensia virginica, Stylophorum diphyllum, and Actaea pachypoda, T. decumbens continued to grow, but this time along with swathes of Trillium flexipes.

Figure 23 Iris cristata (left)

Figure 24 Mertensia virginica

Figure 25 T. flexipes along the Shirley Miller Wildflower Trail

The flower of T. flexipes faces outwards, at right angles from the pedicel. It is variable, but the centre is usually pale with thick cream-yellow anthers.

Figure 26 Actaea pachypoda growing in the same area

17

Figure 27 T. flexipes growing with the yellow celandine poppy and Virginian bluebell.

Figure 28 Detail of T. flexipes

Great Smoky Mountains

Once into the Great Smoky Mountains, Trillium grandiflorum became very common to see. It is easy to recognise with a white open flower, usually held upwards. The colonies were often found facing the sun but in the slight shade of broadleaf trees.

18

Having successfully taken over an area they were the dominant species, where there was one, there were hundreds! They were seen growing with Phacelia fimbriata, however, for a spectacular display, at low elevations in the mountains.

Figure 29 T. grandiflorum on mass

Figure 30 T. grandiflorum with Phacelia fimbriata

Figure 31 Detail of Phacelia fimbriata

19

Figure 32 & Figure 33 Pollination of T. grandiflorum

Figure 34 The pink flush as T. grandiflorum goes over

20

A further two large white species are common in the Great Smoky Mountains, Trillium erectum, and Trillium simile. These two caused much confusion, as they are highly variable, but also prone to hybridisation. Botanist Tom Patrick explained to us that T. erectum has narrow petals that do not overlap, with anthers and ovary at the same height, and T. simile has cup-shaped overlapping petals, with the anthers longer than the ovary.

Figure 35 T. erectum

A clear example of the narrow petals and anthers and ovary at the same height

Figure 36 T. simile

Overlapping petals that do not go pink distinguish this from T. erectum

21

Figure 37 T. erectum with an extra petal, and one less anther

Figure 38 Growing in the acid soils with T. erectum was a great swathe of Erythronium americanum

Figure 39 Sanguinaria canadensis along the same trail, Kanati Trail

22

Trillium luteum was easy to identify, with its sessile yellow petals, and was growing throughout the Great Smoky Mountains. It was seen growing with a number of different plants, each making a beautiful combination. One area where it was growing was in the species rich, White Oak Sinks. White Oak Sinks is formed of limestone, where the older, softer rocks above have eroded away to create a ‘sink’ of limstone. It is within these limestone areas of the park that the most diversity can be found. These plant communities could be replicated, as T. luteum already grows successfully at Kew, perhaps the addition of limestone chippings to the soil may be required.

Figure 40 Galearis spectabilis at White Oak Sinks

Figure 41 The floral carpet at White Oak Sinks

23

Figure 42 T. luteum with Phacelia fimbriata Figure 43 T. luteum with Dodecatheon meadia, Podophyllum peltatum, and Phlox divaricata

Figure 44 Detail of Phlox divaricata Figure 45 Detail of Dodecatheon meadia

24

Figure 44 T. luteum with the purple phacelia, Phacelia bipinnatifida

Figure 46 T. luteum with the red Silene virginica on the Chestnut Top Trail

Figure 47 Silene virginica, only seen at two locations in the mountains

25

Seen only at one location, with only a hand full of plants, was Trillium undulatum. This is an indicator of acid soils, so it is possible that it had been seen at Panthers Creek, but had not been in flower. It is a very distinctive trillium, with it pink centre, however as it requires very acidic soils it may not be easy to grow in the woodland garden at Kew.

Figure 48 The painted trillium, T. undulatum Figure 49 The pollinator gives an indication of the small size of this trillium

Another trillium found on acid soils is . This was seen on the dry slopes of Chestnut Top Trail, under the canopy of pines and chestnut . It grew individually, rather than in clumps, and is not recommended for cultivation, due to its lack of vigour (Case and Case 1997, pg. 88)

Figure 50 T. catesbaei with distinctive recurved petals, and long anthers

Figure 51 T. catesbaei growing through the leaf litter

26

Figure 52 Pink form of T. catesbaei

Had it not been for Tom Patrick, on the Spring Wildflower Pilgrimage, Trillium rugelii would have been missed, even though it had been driven passed on a number of occasions to get to different trail heads. It was close to the road but down a small slope next to a watercourse, and it was well worth seeing, before flying back home. It grew individually and in small clumps, but its population was small.

Figure 53 A grand species, growing with T. luteum

Figure 54 The pink and purple anthers of T. rugelii

27

Figure 55 An unusual form with pale anthers

Figure 56 Tom Patrick giving a tour on the Spring Wildflower Pilgrimage

28

Figure 57 Tom pointed out this unusual form of T. luteum

Figure 58 Tom showed the group this hybrid of T. flexipes and T. erectum

29

Recommendations

After visiting the woodlands of the Cumberland Plateau and the Great Smoky Mountains there are a number of recommendations that could be implemented in woodland garden displays.

On a purely aesthetic level, Trillium decumbens could be considered for the collection at Kew. This species is not currently grown at Kew, but with its unusual habit of lying flat on the ground, it would make an interesting spring ground cover.

A plant community that could be replicated is the one found at White Oak Sink; Trillium luteum, Phlox divaricata, Dodecatheon meadia, and Podophyllum peltatum. This group made a really beautiful display, with purple, yellow and white flowers, and an interesting contrast between the leaf shapes of Podophyllum and T. luteum.

Another combination that would be good for a naturalistic display is that of Trillium grandiflorum and Phacelia fimbriata. The white flowers of both species looked amazing on mass, and would be a great example of what can be found in the Great Smoky Mountains.

For cultivation purposes, most of the trillium species were found growing on sloping ground. The soil was moist but not sodden, and those growing on flat areas were always close to a river or stream, with the soil being a silty clay. Planting trilliums on sloping ground would help excess water to drain away in cultivation, but enough moisture would have to be maintained. Planting on a slope would replicate how they grow in nature, and would display many species’ flowers best, due to the inflorescence hanging down under the leaves, as in such species as T. sulcatum. The species rich areas were the pockets of limestone, rather than acid soils, so the addition of limestone chippings may be worth trying when growing particular species, or at least the pH should be checked.

The leaf litter in which these woodland forbs grew was extremely thick. Feeling self- conscious with a trowel in a national park, it was difficult to gage the exact depth of it, but with year upon year of leaf drop, it was a considerable amount.

30

Expenses

Expense Cost Total Return Flight 636.36 636.36 International Driving 5.50 641.86 Permit Enterprise Car Hire 295.29 937.05 Car Insurance 99.99 1037.04 Road Map 15.99 1053.03 Days Inn Airport 34.32 1087.35 Melia Hotel 161. 58 1248.93 Crash Pad Hostel 38.43 1286.36 Park Place 71.45 1357.81 Comfort Inn 115.98 1473.79 Days Inn, Gatlinburg 147.39 1621.18 Petrol 81.94 1703.12 London Heathrow 34 1737.12 Express Return National Park Permit 12.50 1749.62 Spring Wildflower 8.78 1758.40 Pilgrimage Ticket Food 89.33 1847.73

31

References

Campbell, C, Hudson, W.F, and Sharp A.J., (2006) Great Smoky Mountains Wildflowers 5th Edition. Northbrook, Windy Pines Publishing, LLC.

Case, F.W, and Case, R.B, (1997) Trilliums Oregon, Timber Press

Spira, T.P (2011) Wildflowers and Plant Communities of the Southern Appalachian Mountains and Piedmont, , University of North Carolina Press

32