Try Australian Outback Plantation. If it is from Australia and grows here, they will have it. THey are way out in Tonopah but I know they regularly sell at the DBG plant sale (one coming up 10-13 through 15.) Here is a link that might be useful: Outback Plantation

Here's a whole bunch of plants that will give you that tropical-esque look in Zone 15 (where I live)["st" = inidcates slightly tender]... Trees -- Bauhinia variegata ORCHID TREE (st) x Chiranthofremontia MONKEY HAND FREMONTIA Ensete ventricosum Maurelii ABYSSINIAN BANANA (st) Palms (see separate list) PALMS Podocarpus nagi NAGI Schefflera puekleri TUPIDANTHUS (st) Strelitzia nicholai GIANT BIRD-OF-PARADISE Tabebuia chrysotricha GOLDEN TRUMPET TREE Tabebuia impetiginosa LAVENDER TRUMPET TREE Tristaniopsis laurina ÂElegant RED WATER GUM Palms -- Brahea armata MEXICAN BLUE PALM Brahea edulis GUADALUPE PALM Butia capitata PINDO PALM Chamaerops humilis MEDITERRANEAN FAN PALM Jubaea chilensis CHILEAN WINE PALM Livistona australis AUSTRALIAN FOUNTAIN PALM Livistona chinensis CHINESE FOUNTAIN PALM Phoenix loureiri ASIAN DATE PALM Rhapis excelsa LADY PALM Trachycarpus fortunei WINDMILL PALM Large Shrubs/Small Trees -- Camellia reticulata RETICULATE CAMELLIA Cocculus laurifolius LAUREL-LEAF SNAILSEED Cordyline australis HARDY DRACAENA Fatsia japonica JAPANESE ARALIA Mahonia bealei LEATHERLEAF MAHONIA Mahonia lomariifolia CHINESE MAHONIA Melianthus major HONEYBUSH Medium Shrubs -- Abutilon FLOWERING MAPLE, CHINESE LANTERN Anigozanthos KANGAROO PAWS Aucuba japonica JAPANESE AUCUBA Cestrum nocturnum NIGHT-BLOOMING JESSAMINE (st) Cordyline stricta AUSTRALIAN TI PLANT (st) Cycas revoluta CYCAD, SAGO "PALM" Doryanthes palmeri SPEAR LILY Fuchsia fulgens MEXICAN FUCHSIA Fuchsia triphylla (and hybrids) BUSH FUCHSIA Hibiscus rosa-sinensis (hardiest: ÂAgnes GaltÂ, ÂBrilliantÂ, ÂCrown of BohemiaÂ, ÂRoss EsteyÂ, ÂWhite WingsÂ) HIBISCUS (st) Hydrangea quercifolia OAKLEAF HYDRANGEA Phormium tenax hybrids NEW ZEALAND FLAX Strelitzia reginae BIRD-OF-PARADISE Small Shrubs/Big Perennials -- Acanthus mollis BEARÂS BREECH x Amarcrinum memoria-corsii HYBRID CRINUM Anigozanthos KAGAROO PAW Aristea ecklonii BLUE STARS Aspidistra elatior CAST-IRON PLANT Musella lasiocarpa GOLDEN LOTUS BANANA Phormium tenax hybrids (esp. ÂApricot QueenÂ, ÂDazzlerÂ, ÂDuetÂ, ÂMaori MaidenÂ, ÂMaori QueenÂ, ÂMaori SunriseÂ, ÂRainbow WarriorÂ, ÂShirazÂ, ÂSurfer NEW ZEALAND FLAX Zantedeschia aethiopica ÂGreen Goddess GIANT CALLA-LILY Ornamental Grasses (And Grasslike Plants) -- Austrostipa ramosissima AUSTRALIAN PLUME GRASS Baumea rubiginosa ÂVariegata STRIPED RUSH Carex atrata BLACK ALPINE SEDGE Carex dissita BUSH SEDGE Carex dolichostachya ÂKaga-nishiki GOLD FOUNTAIN SEDGE Carex elegantissima ÂVariegata GOLDEN-EDGED SEDGE Carex morrowii cultivars JAPANESE SEDGE Carex phyllocephala 'Sparkler' SPARKLER SEDGE Carex tumicola BERKELEY SEDGE Chondropetalum tectorum CAPE RUSH Elegia capensis BROOM REED Elegia equisetacea HORSETAIL RESTIO Hakonechloa macra ÂAureola JAPANESE FOREST GRASS Rhodocoma capensis ELEGANT RESTIO Rhodocoma gigantea DEKRIET, BAMBOO RESTIO Sasa palmata (can be a rampant spreader) PALM GRASS Setaria palmifolia PALM GRASS (st) Xanthorrhoea johnsonii AUSTRALIAN GRASS TREE Small Clumping Bamboos -- Bambusa multiplex rivierorum CHINESE GODDESS Fargesia murielae UMBRELLA BAMBOO Fargesia nitida FOUNTAIN BAMBOO Otatea acuminata aztecorum MEXICAN WEEPING BAMBOO Bulbs/Annuals -- Amaryllis belladonna NAKED LADIES Cyclamen persicum CYCLAMEN Iris ensata JAPANESE IRIS Ricinus communis CASTOR BEAN (st) Solenostemon scutellarioides COLEUS (st) Small-Medium Perennials -- Astelia nervosa chathamica SILVER SPEAR Astelia nivicola ÂRed Gem RED GEM ASTELIA Begonia x richmondensis RICHMOND BEGONIA Bergenia cordifolia BERGENIA Clivia miniata FLAME LILY Clivia nobilis RED LILY (st) Dianella intermedia NEW ZEALAND BLUE-BERRY Dianella tasmanica (esp. ÂVariegataÂ) FLAX LILY Grasses (see separate list) GRASSES Helleborus lividus CORSICAN HELLEBORE Helleborus x stearnii HYBRID HELLEBORE Heuchera CORAL BELLS Iris Louisiana LOUISIANA IRIS Liriope LILY TURF Ophiopogon jaburan GIANT LILY TURF Tradescantia pallida ÂPurpurea PURPLE HEART (st) Soleirolia soleirolii BABYÂS TEARS Zantedeschia aethiopica CALLA-LILY Container Specimens -- Brugmansia ANGELÂS TRUMPET (st) Ipomoea batatas ORNAMENTAL SWEET POTATO (st) Lotus berthelotii, maculatus, and hybrids PARROTÂS BEAK (st) Rhododendrons (Vireyas) MALAYSIAN RHODODENDRON (st) Vines-- Akebia quinata FIVELEAF AKEBIA Bougainvillea (ÂHawaiiÂ, ÂLavender QueenÂ, ÂSan Diego RedÂ, B. spectabilis are the most winter hardy) BOUGAINVILLEA (st) Clematis x cartmanii ÂAvalanche AVALANCHE CLEMATIS Distictis buccinatoria BLOOD-RED TRUMPET VINE (st) x Fatshedera lizei ARALIA IVY Hedera canariensis variegata VARIEGATED ALGERIAN IVY Hydrangea anomala petiolaris CLIMBING HYDRANGEA Lonicera hildebrandtiana BURMESE HONEYSUCKLE (st) Macfadyena unguis-cati CATÂS-CLAW Pandorea jasminoides BOWER VINE Passiflora alata ÂRuby Glow RUBY GLOW PASSION FLOWER Passiflora caerulea ÂConstance Elliott CONSTANCE ELLIOTT P.V. Passiflora hybrids (the hardiest: ÂBlack KnightÂ, ÂBountiful BeautyÂ, ÂElizabethÂ, ÂFredericÂ, ÂIncenseÂ, ÂLavender LadyÂ, ÂNancy GarrisonÂ, ÂPossum PurpleÂ, ÂRed RoverÂ, ÂRed SunsetÂ, ÂSusan Brigham HYBRID PASSION VINES Passiflora incarnata MAYPOP Passiflora jamesonii CORAL PASSION VINE Passiflora mollissima BANANA PASSION VINE Solanum jasminoiodes WHITE POTATO VINE Vigna caracalla SNAIL VINE (st) Ferns -- Adiantum capillus-veneris SOUTHERN MAIDENHAIR Adiantum aleuticum WESTERN MAIDENHAIR Adiantum pedatum FIVE-FINGER MAIDENHAIR Asplenium bulbiferum MOTHER FERN Asplenium scolopendrium HARTÂS TONGUE FERN Blechnum occidentale HAMMOCK FERN Blechnum spicant DEER FERN Cyathea cooperi AUSTRALIAN TREE FERN (st) Cyrtomium falcatum HOLLY FERN Dicksonia antartica TASMANIAN TREE FERN (st) Microlepia strigosa LACE FERN Nephrolepis cordifolia SOUTHERN SWORD FERN Platycerium bifurcatum STAGHORN FERN Polypodium aureum HAREÂS-FOOT FERN Polystichum munitum SWORD FERN Pyrrosia lingua JAPANESE FELT FERN Pyrrosia lingua ÂCristata CRESTED JAPANESE FELT FERN Pyrrosia polydactyla PALM-LEAF FERN Rumohra adiantiformis LEATHERLEAF FERN Woodwardia fimbriata GIANT CHAIN FERN Hardy (?) Bromeliads -- Aechmea recurvata and vars benrathii and ortgiesii Billbergia distachia and var maculata Billbergia nutans Billbergia pyramidalis and var striata Billbergia ÂSanta Barbara Bromelia balansae Dyckia ferox Dyckia fosteriana Dyckia fosteriana x brevifolia Fasicularia pitcairnifolia Puya alpestris Puya berteroniana Puya chilensis Puya raimondii Puya spathacea Tillandsia grandis Tillandsia ionantha Tillandsia recurvata and even... CREATING A TROPICAL-ESQUE GARDEN USING CALIFORNIA NATIVE PLANTS Medium to Large Trees -- Lithocarpus densiflora TANBARK OAK Quercus tomentella ISLAND OAK Umbellularia californica CALIFORNIA BAY-LAUREL Small Trees -- Fremontodendron californicum FLANNELBUSH Garrya elliptica SILKTASSEL Lyonothamnus floribundus asplenifolius SANTA CRUZ IRONWOOD Prunus illicifolia lyonii CATALINA CHERRY Smallest trees (actually large shrubs but, with selective pruning,Â) -- Aesculus californica CALIFORNIA BUCKEYE Calycanthus occidentalis CALIFORNIA SPICEBUSH Dendromecon harfordii ISLAND BUSH POPPY Comarostaphylis diversifolia SUMMER HOLLY Fremontodendron californicum FLANNEL BUSH, FREMONTIA Myrica californica PACIFIC WAX MYRTLE Rhamnus californica COFFEEBERRY Sambucus mexicana BLUE ELDERBERRY Really Big Shrubs (up to 15-20 feet and sometimes more) -- (eventually, these can be trained as small trees by "limbing up", if so desired) Comarostaphylis diversifolia SUMMER HOLLY Dendromecon harfordii ISLAND BUSH POPPY Fremontodendron californicum FLANNELBUSH Garrya elliptica SILKTASSEL Myrica californica PACIFIC WAX MYRTLE Sambucus mexicana BLUE ELDERBERRY Large Shrubs (8-15 feet) -- Calycanthus occidentalis CALIFORNIA SPICEBUSH Dendromecon harfordii ISLAND BUSH POPPY Fremontodendron ÂCalifornia Glory C. G. FREMONTIA Fremontodendron ÂPacific Sunset P. S. FREMONTIA Fremontodendron ÂSan Gabriel S. G. FREMONTIA Garrya elliptica COAST SILK-TASSEL Myrica californica PACIFIC WAX MYRTLE Rhamnus californica COFFEEBERRY Medium Shrubs (5-10 feet)-- Dendromecon rigida BUSH POPPY Fremontodendron ÂKen Taylor K. T. FREMONTIA Mahonia ÂGolden Abundance G.A. BARBERRY Mahonia nevinii NEVINÂS BARBERRY Mahonia ÂSkylark SKYLARK MAHONIA Rhamnus californica ÂEve CaseÂ, ÂMound San Bruno COFFEEBERRY Small Shrubs and Taller Subshrubs (2-5 feet) -- Carpenteria californica ÂElizabeth BUSH ANEMONE Galvezia juncea BAJA BUSH SNAPDRAGON Galvezia speciosa ISLAND SNAPDRAGON Garrya veatchii SILK-TASSEL BUSH Mimulus aurantiacus Hybrids BUSH MONKEY FLOWER Vaccinium ovatum (taller in shade) EVERGREEN HUCKLEBERRY Large Perennials -- Romneya coulteri and hybrids MATILLIJA POPPY Romneya trichocalyx MATILLIJA POPPY Woodwardia fimbriata CHAIN FERN Medium Perennials -- Adiantum capillus-veneris MAIDENHAIR FERN Adiantum pedatum FIVE-FINGER MAIDENHAIR Blechnum spicant DEER FERN Epipactis gigantea GIANT STREAM ORCHID Iris macrosiphon BIG-TUBE IRIS Penstemon centranthifolius SCARLET BUGLER Penstemon spectabilis SHOWY PENSTEMON Polypodium glycyrrhiza LICORICE FERN Polypodium scouleri WESTERN LEATHERLEAF FERN Polystichum dudleyi DUDLEYÂS SWORDFERN Polystichum munitum WESTERN SWORD FERN Polystichum munitum WESTERN SWORD FERN Small Perennials -- Adiantum aleuticum ALEUTIAN MAIDENHAIR FERN Adiantum jordani JORDANÂS MAIDENHAIR FERN Anemopsis californica YERBA MANSA Asarum lemmonii WILD GINGER Athyrium felix-femina LADY FERN Chlorogalum pomeridianum AMOLE, SOAP PLANT Heuchera maxima and hybrids CORAL BELLS Iris douglasiana DOUGLAS IRIS Iris Pacific Coast Hybrids PCH IRIS Lilium humboldtii HUMBOLDT LILY Lilium washingtonianum WASHINGTON LILY Lobelia cardinalis CARDINAL LOBELIA Lobelia dunnii BLUE LOBELIA Mimulus cardinalis SCARLET MONKEY FLOWER Mimulus guttatus CREEK MONKEY FLOWER Salvia spathacea HUMMINGBIRD SAGE Sisyrinchium bellum BLUE-EYED GRASS Sisyrinchium californicum GOLDEN-EYED GRASS Verbena lilacina LILAC VERBENA Grasses and Grasslike Plants -- Carex barbarae SANTA BARBARA SEDGE Carex nudata CALIFORNIA BLACK-FLOWERING SEDGE Carex pansa CALIFORNIA MEADOW SEDGE Carex praegracilis CLUSTERED FIELD SEDGE Carex spissa SAN DIEGO SEDGE Carex tumulicola BERKELEY SEDGE Cyperus eragrostis TALL FLAT SEDGE Deschampsia caespitosa TUFTED HAIRGRASS Deschampsia elongata SLENDER HAIRGRASS Eleocharis macrostachya SPIKE RUSH Eleocharis montevidensis SPIKE RUSH Equisetum hyemale HORSETAIL Juncus effusus COMMON RUSH Juncus patens RUSH Nolina parryi BEAR GRASS Groundcovers -- Arctostaphylos ÂPacific Mist P. M. MANZANITA Arctostaphylos uva-ursi cultivars KINNICK-KINNICK Asarum caudatum WILD GINGER Asarum hartwegii HARTWEG'S GINGER Carex barbarae SANTA BARBARA SEDGE* Carex nudata CALIFORNIA BLACK-FLOWERING SEDGE Carex pansa CALIFORNIA MEADOW SEDGE* Carex praegracilis MOUNTAIN MEADOW SEDGE* Carex spissa SAN DIEGO SEDGE Carex tumulicola BERKELEY SEDGE* Ceanothus gloriosus cultivars POINT REYES CEANOTHUS Fragaria chiloensis BEACH STRAWBERRY Mahonia repens CREEPING BARBERRY Rhamnus californica ÂSeaview LOW COFFEEBERRY Ribes viburnifolium EVERGREEN CURRANT Satureja douglasii YERBA BUENA Vancouveria planipetala INSIDE-OUT FLOWER Joe

Yes you can cut a Cyathea cooperii off if it gets too tall. Keep the top plus enough of the top trunk to replant at the height you want plus half a metre to be buried in soil. . The bottom part will not regenerate and needs to be removed. Trim back the old fronds being carefull not to damage the new unfurling ones. Replant in fresh slightly acid soil, give it some organic fertilizer, water the trunk and base well but not the fronds. Make sure there is adequate drainage. give the plant some dappled shade if you can.

The soil just under the base of the tree may be damp, but I'm betting the rest of the soil in that pot is bone dry. That tree looks like it's dying of lack of water. If I were you I'd take it out of the pot and examine the soil. Sometimes potting mix can seem wet on the surface but have large dry pockets down deeper. If it's a peat based mix, and most store bought are, if it gets too dry one time, it's almost impossible to re-wet from just watering from the top. It would need to be submerged in a larger pot that does not drain, and really let it soak for 24 hours. Then remove and water normally. Imo, 2 weeks without watering is way too long.