Rebecca, You don't necessarily have to go to the local nursery; just always check out potential suppliers on Garden Watchdog before ordering. You can also use Dave's PlantScout to locate a nursery that sells what you are looking for, and then go from there directly to Garden Watchdog. Look on the bright side, you could have ordered from TyTy or Aaron's Nursery (the real "worst nurseries in the country"). BTW, if you try to look TyTy up on Garden Watchdog, it doesn't show up. They had an EXTREMELY negative rating and, from what I've heard, threatened to sue Dave's if they weren't removed. Here is a link that might be useful: Spring Hill on Garden Watchdog

I've seen them sold as standards at some nurseries and sometimes even big box stores. There's an online place offering already-trained standards here. I have seen large ROS trees around my area - with thick trunks and perhaps 15 - 20 or more ft. tall, which is incredible. There are a number of large ones about 15ft tall (with tons of seedlings) at the back of my sister's property at the edge of the woods along her creek. I'm wondering if the large-trunked ones that I've seen are a different species of temperate Hibiscus or were grafted onto some tree rootstock many years ago or what. I know that flowering shrub standards are often grafted onto ligustrum as a rootstock as it is fast-growing, hardy, and tends to keep a straight smooth trunk. The flower is unmistakable on them though. The ROS's I grew up with tended to stay about 7-8ft at maturity.

Image by: Clare_CAMichelia Figo var. SkinnerianaWhich Shrubs Smell Good? -     Fragrant Plants       The following list of fragrant plants was compiled by Clare_CA.  Please note, this list is considered a work in progress with additional fragrant plants added over time.       Plant Name Abelia mosanensis ‘bridal bouquet,’ fragrant abelia Abelia trilora Acidanthera, 'Peacock orchid' Agastache ‘Summer Breeze’ Agastache foeniculum Anise Hyssop Aglaia odorata Aloysia virgatas, Sweet Almond Azara microphylla Beaumontia grandiflora Blanc Double de Coubert rugosas Boronia Boronia megastigma Brassavola nodosa (Lady of the Night orchid) Brugmansia Brunfelsia americana Brunfelsia australis Brunfelsia Nitida (Lady of the Night) Brunfelsia pauciflora Buddleia Asiatica Calycanthus occidentalis, Spice Bush Cananga odorata Carolina allspice, Calycanthus sp. Centaurea moschata Sweet Sultan (Annual) Cestrum diurnum Cestrum nocturum Chimonanthus praecox Chlidanthus fragrans Perfumed Fairy Lily (Bulb) Choisya ‘Aztec Pearl,’ Aztec Pearl Mexican Orange Choysia ternata, Mexican Mock Orange Cimicifuga 'Hillside Black Beauty' Citrus (esp. ‘Bouquet de Fleurs’) Citrus (tree) Clematis Montana Clematis, Sweet Autumn Clematis Clerodendron phillipinum Clerodendrum trichotomum Clethra alnifolia Clethra 'Ruby Spice' Coleonema pulchrum/Breath of Heaven Crinum odorata Crinum powellii and C. moorei Daphne bholua Daphne 'Carol Mackie' Daphne odora Datura Inoxia Datura Metel Datura Stramonium var Tatula Datura wrightii Dianthus ‘Bath’s Pink’  Diplarrhena moraea ‘Slieve Donard,’ White Flag Iris Dipogon lignosus Diurnum Double Delight - Hybrid Tea Rose Dracaena fragans Eriodictyon capitatum Lompoc Yerba Santa Erysimum cheiri, Wallflower  (Annual) Eupatorium ligustrinum Euphorbia leucocephala Freesia (Bulb) Gardenia angusta Gardenia 'White Gem' Gladiolus callianthus Abyssinian Sword Lily (Bulb) Gladiolus tristis Marsh Afrikaner (Bulb) Hansa - Rugosa Rose Hedychium coronaria, common white ginger Hedychium coronarium Hedychium flavescens/gardnerianum/flavum/coronarium Hedychium gardnerianum is an outstanding ginger lily. Hedysarum coronarium French Honeysuckle Helichrysum (Licorice plant) Hemerocallis ‘Fragrant Treasure,’ Frangrant Treasure Daylily Hemerocallis ‘Hyperion,’ Hyperion Daylily Hemerocallis ‘Sherwood Gladiator,’ Sweet Gladiator Daylily Hemerocallis citrina, Lemon Daylily Hemerocallis lilioasphodelus, Lemon Lily Hemerocallis minor, Dwarf Daylily Holarrhena densiflora (Jasmine Tree) Hoya lacunosa Hyacinths, Nicotiana, oriental lilies, and easter lilies Hymenocallis ‘Erotica’ Fragrant Basket Lily (Bulb) Hymenocallis ‘Sulphur Queen’ Sulphur Queen B. Lily (Bulb) Hymenocallis ‘Tropical Giant’ Hybrid Basket Lily (Bulb) Hymenocallis narcissiflora (+ ‘Advance’) Peruvian Daffodil (Bulb) Hymenocallis x festalis ‘Zwanenburg’ Primrose Spider Lily (Bulb) Hymenocallis x festalis Spider Lily (Bulb) Hymenosporum flavum, Australian Frangipani, Sweetshade (tree) Illicium Floridanum Jasmine molle Jasminum Azoricum Jasminum humile, Italian/Yellow Jasmine Jasminum officinale, Poet’s Jasmine Jasminum polyanthum, Pink/Winter Jasmine Jasminum Sambac Flore Plena Jasminum Sambac, Belle of India Jasminum Sambac, Grand Duke Jasminum Sambac, Maid of Orleans Jasminum x stephanense, Stephan Jasmine Lathyrus odoratus, Sweet Pea (Annual) Laurus nobilis, Grecian Bay Laurel (tree) Lavandula, Lavenders (many) Lepechinia hastata, Baja Pitcher Sage Leptospermum petersonii,  Lemon-scented Tea Tree (tree) Lillium "Le Reve" Lobularia maritima, Sweet Alyssum (Self-sowing Annual) Lonicera Lonicera japonica Luculia intermedia/pinceana-Luculia Luculia pinceana/intermedia/gratissimus Madame Isaac Pereire, Antique Rose Magnolia ‘Timeless Beauty’ (tree) Magnolia grandiflora, Southern Magnolia (tree) Magnolia hypoleuca Magnolia salicifolia ‘Kockanakee’ (tree) Magnolia salicifolia ‘W.B. Clarke’ (tree) Magnolia seiboldii, Oyama Magnolia Magnolia stellata, Star Magnolia Magnolia Virginiana Magnolia x loebneri ‘Ballerina’ (tree) Magnolia x loebneri ‘Spring Snow’ (tree) Magnolia x stellata ‘Royal Star’ (tree) Magnolia x stellata ‘Waterlily’ (tree) Magnolia x wieseneri Mandevilla laxa Matthiola incana, Stock (Annual) Matthiola longipetala bicornis, Evening-scented Stock (Annual) Melanoselinum decipiens Michelia champaca Michelia chapensis Michelia doltsopa  Michelia figo, Banana Shrub Michelia Wilsonii (sinensis) Michelia x alba Michelia x foggii ‘Jack Fogg’ (tree) Milletia reticulata Mirabilis, Four o'clocks Mitriostigma Axillare or African Gardenia Montanoa grandiflora, Narcissus jonquilla ‘Kinglet’, ‘Sweetness’, ‘Vireo’Jonquil (Bulb) Narcissus papyraceus, Paper Whites (Bulb) Narcissus tazetta, Narcissus (Bulb) Narcissus x odorus, Campernelle Jonquil (Bulb) Nicotiana alata Nicotiana sylvestris Orchid Vanda merillii Osmanthus fragrans, Sweet Olive Passiflora Alata “Ruby Glow” Passiflora belotti Passiflora colinvauxii (honeysuckle fragrance) Passiflora helleri Passiflora Incense Passiflora serratodigitata Passiflora sprucei Pelargonium , Scented Geraniums (all*) -- Pelargonium ‘Filicifolium’  Balsam Pelargonium ‘Tutti-Fruiti’ Tutti-Fruiti Pelargonium capitatum ‘Attar of Roses’ Old Rose Pelargonium crispum ‘Peach Cream’ Peach Pelargonium crispum ‘Prince of Orange’ Orange Pelargonium crispum Lemon Pelargonium graveolens ‘Rober’s Lemon Rose’ Lemon-rose Pelargonium graveolens Rose Pelargonium grossularioides Coconut Pelargonium nervosum ‘Torento’ Ginger Pelargonium nervosum Lime Pelargonium odoratissimum, Apple Pelargonium quercifolium, Pelargonium Almond Pelargonium scabrum ‘M. Ninon’ Apricot Pelargonium scarboravia Strawberry Pelargonium tomentosum ‘Chocolate Joy’ Chocolate-mint Pelargonium tomentosum Peppermint Pelargonium x fragrans ‘Nutmeg’ Nutmeg Pelargonium x fragrans ‘Old Spice’ Old Spice Philadelphus ‘Fallbrook’, ‘Galahad’ Mock Orange Philadelphus microphyllus Small-leaved Mock Orange Philadelphus x virginalis ‘Glacier’ Dwarf Mock Orange Pittosporum tobira Japanese Mock Orange Pittosporum tobira Mock Orange Pittosporum undulatum, Victorian Box Plumeria (tree) Polianthes tuberosa, Tuberose (Bulb) Portulandia grandiflora Primula florindae, the Tibetan Primrose Prospero & Golden Celebration - David Austin Roses Psoralea pinnata Quisqualia indica, Rangoon Creeper Reseda odorata Mignonette  (Annual) Rhododendron atlanticum fragrance of gardenia and clove Ribes aureum, Golden Currant  Rosas Typhoo Tea Rose, (The Apothecary Rose; deep pink) Rose, Angel Face (floribunda; mauve) Rose, Apricot Nectar (floribunda; apricot blend) Rose, Arizona (grandiflora; orange blend) Rose, Betty Prior (floribunda; medium pink) Rose, Buff Beauty (Hybrid Musk; apricot blend) Rose, Cathedral (floribunda; apricot blend) Rose, Chinatown (floribunda; deep yellow) Rose, Chrysler Imperial (HT; also cl.; crimson) Rose, Command Performance (HT; orange-red) Rose, Comte de Chambord (Portland; pink blend) Rose, Crimson Glory (HT; also cl.; crimson) Rose, Dainty Bess (HT; light pink; single) Rose, Double Delight (HT; red-white bicolor) Rose, Electron (HT; deep pink) Rose, Etoile de Holland (HT; also cl.; crimson) Rose, Evelyn (English; apricot-pink blend) Rose, Fashion (floribunda; orange-pink blend) Rose, Fragrant Cloud (HT; coral red-orange blend) Rose, Fragrant Hour (HT; orange-pink blend) Rose, François Dubreuil (Tea; dark red) Rose, Friendship (HT; deep pink) Rose, Granada/Donatella (HT; red-yellow blend) Rose, High Hopes (climber; med. pink) Rose, Intrigue (floribunda; mauve blend) Rose, Ispahan (Damask; medium pink) Rose, Jacques Cartier (Portland; light pink) Rose, Jadis (HT; pink) Rose, Just Joey (HT, orange blend) Rose, Lemon Spice (HT; pale yellow) Rose, Love (Gr.; red blend) Rose, Marechal Niel (cl. Noisette; softest yellow) Rose, Mirandy (HT; garnet red) Rose, Mister Lincoln (HT; dark red) Rose, Nuage Parfumé (HT; also cl.; coral-orange-red blend) Rose, Oklahoma (HT; deep red) Rose, Papa Meilland (HT; deep crimson) Rose, Perfume Delight (HT; medium pink) Rose, Rosa gallica officinalis/duplex Rose, Rosa gallica versicolor (Gallica; striped pink) Rose, Rosa x damascena bifera (Damask, Rose of Castile; m. pink) Rose, Royal Amethyst (HT; lavender) Rose, Saratoga (floribunda; white) Rose, Sheer Bliss (HT; white/pink blend) Rose, Simplicity (floribunda; light pink) Rose, Spanish Sun (floribunda; deep yellow) Rose, Spartan (floribunda; orange-red blend) Rose, Sunsprite (floribunda; deep yellow) Rose, Sutter’s Gold (HT; orange blend) Rose, Sweet Surrender (HT; silvery med. pink) Rose, Tiffany (HT; pink blend) Rose, White Lightnin’ (GR; white) Rose, Wild Spice (shrub) Rosmarinus officinalis Salvia clevelandii Salvia clevelandii 'Aromas' Salvia clevelandii/Cleveland Sage Salvia elegans, Pineapple Sage Salvia melissodora Grape-scented Sage Sarcococca Hookeriana Humilis Sarcococca rustifolia Scentimental, Hybrid Tea Solandra maxima Sombreuil climbing antique Stephanotis floribunda Sweet Afton Sweet Chariot - miniature "hanging basket" rose Syringa microphylla 'Superba' Tagetes nelsonii, Citrus Marigold Telosma cordata, Pakalana Vine Thornless Honey Locust-Gleditsia triacanthos f. inermis Tilia cordata, Little Leaf Linden Trachelospermum jasminoides, Star Jasmine Ugni molinae, Chilean Guava Umbellularia californica California Bay Laurel (tree) Verbena x hybrida ‘Defiance,’ Defiance Verbena Viburnum carlesi 'Compactum' Viburnum Carlesii (clove scent) Viburnum, Korean Spice Viola Odora Weigela florida 'Variegata nana' Wild clover, Melilotus alba Wintersweet, Chimonanthus praecox Wisteria    

Not necessarily. You did not identify what "not growing well" means, how far apart they all are, how old and what type/variety of hydrangea and rhododendron you have so, there could be many other reasons. Just an example... consider sunlight: Rose of Sharon (RoS) may be in full sun; some hydrangeas/rhododendrons may not like the full sun growing conditions. But, I do hear you. I would not try to grow plants too close to RoS because the RoS may eventually encroach on them: RoS reproduces with new shoots coming up from the ground right next to itself so, if left unchecked, the plant can quickly get out of control in your garden. RoS can also reseed abundantly so, be ready to remove additional plants appearing in unwanted areas near or far away. A metal barrier in between them might minimize the underground roots problem. Pruning of the new shoots and deadheading of spent flowers can also help. There are seedless varieties of RoS out there like Orchid Satin.