"6 to 8 feet" isn't really a tree. Here's a few medium to large shrubs that you can "limb up" to create a multi-trunked tree look; although they'll want to get taller than 8 feet, you can keep them at 8 with creative pruning: Acca (Feijoa) sellowiana PINEAPPLE GUAVA Arbutus unedo 'Compacta' STRAWBERRY TREE Arctostaphylos ÂAustin Griffiths AUSTIN GRIFFITHS MANZANITA Arctostaphylos densiflora ÂHarmony HARMONY MANZANITA Arctostaphylos manzanita ÂDr. Hurd DR. HURD MANZANITA Arctostaphylos pajaroensis ÂParadise PAJARO MANZANITA Banksia ashbyi ASHBYÂS BANKSIA Banksia brownii FEATHER-LEAD BANKSIA Banksia coccinea SCARLET BANKSIA Banksia menziesii RASPBERRY FROST Callistemon citrinus ÂMauve Mist M. M. BOTTLEBRUSH Callistemon citrinus LEMON BOTTLEBRUSH Callistemon phoeniceus LESSER BOTTLEBRUSH Callistemon rigidus STIFF BOTTLEBRUSH Callistemon salignus WHITE BOTTLEBRUSH Cercis occidentalis WESTERN REDBUD Comarostaphylis diversifolia SUMMER HOLLY Cotinus coggygria SMOKETREE Escallonia laevis PINK ESCALLONIA Escallonia x exoniensis ÂBalfouriÂ, ÂFrades HYBRID ESCALLONIA Grevillea asplenifolia FERN-LEAF GREVILLEA Grevillea ÂHoneygemÂ, ÂIvanhoeÂ, ÂLong JohnÂ, ÂPoorinda BlondieÂ, ÂRed HooksÂ, HYBRID GREVILLEA Grevillea hookeriana TOOTHBRUSH GREVILLEA Grevillea olivacea OLIVE-LEAF GREVILLEA Grevillea victoriae ÂMurray Valley Queen M. V. Q. GREVILLEA Hakea arachaeoides SPIDER HAKEA Hakea bucculenta HOT POKERS Hakea francisiana PINK SPIKE HAKEA Hakea laurina SEA URCHIN, PINCUSHION TREE Leptospermum lanigerum WOOLY TEA TREE Leptospermum polygalifolium ÂYarra River RED SPIRE TEA TREE Leptospermum scoparium ÂHelene StrybingÂ, ÂKeatleyiÂ, ÂPink DamaskÂ, ÂPink PearlÂ, NEW ZEALAND TEA TREE Leucospermum reflexum RED ROCKET Melaleuca armillaris FEATHERY MELALEUCA Melaleuca bracteata WHITE CLOUD TREE Melaleuca decussata LILAC MELALEUCA Melaleuca elliptica GRANITE BOTTLEBRUSH Melaleuca ericifolia HEATH BOTTLEBRUSH Melaleuca hypericifolia HILLOCK BUSH Melaleuca nesophila PINK MELALEUCA Pinus contorta contorta SHORE PINE Pittosporum crassifolium KARO Pittosporum eugenioides TARATA Pittosporum tenuifolium KOHUHU, TAWHIWI Prunus illicifolia HOLLYLEAF CHERRY Psidium cattleianum STRAWBERRY GUAVA Regelia velutina BARRENS REGELIA Rhaphiolepis ÂMajestic Beauty (multi) M. B. INDIAN HAWTHORNE Viburnum suspensum SANDANKWA Xylosma congestum SHINY XYLOSMA Joe

There aren't a lot of truly "dwarf trees". You say you don't want a "bush or shrub" but your limit of 15 feet pretty much rules out true trees (which many botanists say start at 20 feet) and leaves you with the opportunity to take a tall-growing shrub and train it to look like a tree. Shrubs trained as such -- single trunk with a crown -- are called "standards". Usually marketed as "patio trees". Here's a few ideas: Acca (Feijoa) sellowiana PINEAPPLE GUAVA Banksia ashbyi ASHBY'S BANKSIA Banksia coccinea SCARLET BANKSIA Ceanothus arboreus 'Blue Mist', 'Cliff Schmidt', 'Thundercloud', 'Trewithen Blue' TREE CEANOTHUS Ceanothus thyrsiflorus 'Snow Flurry' SNOW FLURRY CEANOTHUS Cercocarpus betuloides MOUNTAIN IRONWOOD Comarostaphylis diversifolia SUMMER HOLLY Cotinus coggygria SMOKETREE Escallonia laevis PINK ESCALLONIA Escallonia x exoniensis 'Balfouri', 'Frades' HYBRID ESCALLONIA Grevillea 'Honeygem', 'Ivanhoe', 'Long John', 'Poorinda Blondie', 'Red Hooks' HYBRID GREVILLEA Leptospermum lanigerum WOOLY TEA TREE Leptospermum polygalifolium 'Yarra River' RED SPIRE TEA TREE Melaleuca decussata LILAC MELALEUCA Melaleuca elliptica GRANITE BOTTLEBRUSH Osmanthus fragrans SWEET OLIVE Pittosporum crassifolium KARO Pittosporum eugenioides TARATA Pittosporum tenuifolium KOHUHU, TAWHIWI Psidium cattleianum STRAWBERRY GUAVA Rhaphiolepis 'Majestic Beauty' M. B. INDIAN HAWTHORNE All of these need some work (pruning) to make them look like a tree (single trunk, crown). Some more than others (as already pointed out with Cercis occidentalis). You didn't say why you need it to top out at 15 feet. Are there utility wires or a view from the house or? Joe

I haven't tried growing any California fuchsias from seed, but I bought two in one-gallon pots. I think one of mine died of drought; the other is still alive. My understanding is that they're not supposed to be very picky about drainage or watering or anything else. Some drainage is good, but it doesn't have to be excellent drainage. And they're supposed to be fairly drought-tolerant, at least after a year or so. But for the first year, I'd recommend giving them a fair amount of water, since mine seemed to need it.

So glad you got it to work. That photo is fantastic! Please post more when you can, I know that your gardens must be beautiful.