I think you're biggest change in gardening thinking will be that it does not rain from May to November. So you have to supply the water, or it does not happen. There is no lush "wild" greenery like back East, unless you count dusty-looking half dead chaparral plants that hunker down thru the dry season. You have to pay big bucks for water. While 1/6 acre lots are the norm here, that's about all you can afford to pay to irrigate (it's about all you can afford to buy anyway in urban areas, cause real estate prices are out of sight here in California). You will probably have to water twice a week to grow the same plants in Walnut Creek that you grew in Michigan. The next biggest difference is that it is obviously a lot warmer in winter. There are usually enough frosty nights that growing extremely sensitive tropicals means running out in the evening to cover them for the night, but most people can't resist giving them a try. Most hardy plants keep their top growth, and may even make some active growth in the winter, but stuff usually just sits still until it starts to warm up in late February (it's cold from mid-November til sometime in late February to mid March) We get most of our rain during that time frame too. You can't mulch heavily, like you do back East to protect tender plants because it is warm enough during the day for fungal growth to cause rot if the crown of the plant is covered.

Thank you, Jim and Cottagegarden for reviving this thread. I really appreciate the company of kind, and positive visitors to this forum. Like Cottagegarden, I bought 2 soil-test kits from local stores: Lowe and HomeDepot. They are totally useless and gave false result. Then I paid $20 for EarthCo. (professional soil-testing company) and my soil test came back high pH at 7.7, and deficient in everything, plus barely adequate in calcium ... I was so sure that my soil has plenty of calcium !! I'm next to a limestone quarry. For years I disagree with my neighbor on calcium. He insisted that his tomato in pots are lacking in calcium (blossom end-rot) ... He's right, after seeing how mixing gypsum (calcium sulfate) into the soil made 1st-year band-size La Reine went beserk with buds: due to winter-kill, it's only 8 inch. tall, but with 10 buds !! But the plant is stunt & brown leaves, and the blooms are small. I forgot to give it sulfate of potash (it should be twice more potassium than calcium). Yes to mixing gypsum into planting hole, but no more than 10% (I spent hours researching on the right % to mix in). I broke that rule many times, and end up with stunt plants & leaves showing potassium deficiency. Too much calcium drives down potassium. If you have a large garden, soil can vary: some part can be alkaline if watered frequently with high pH tap water. Most tap water are alkaline, I already tested a few with fish-tank litmus paper, even mineral bottled water has pH over 8. Some part of a garden can be acidic (if get rain water only, pH at 5.6). My soil test recommend mixing sulfur into clay. BAD ADVICE !! That was expensive and killed tons of earthworms. I like gypsum better, less caustic & cheaper ($4 for 25 lb. at Menards). Gypsum is great in breaking up compacted clay, provides calcium, plus de-salt soil. I moved 4 roses this spring: The ones that didn't get gypsum in the planting hole were slower to recuperate. The one that got gypsum in the planting hole, was VERY FAST in pumping out buds. See Duchess de Rohan below, 2 weeks after moving, with lots of buds. I moved that one since it was in too much shade, zero blooms. After moving to more sun, it exploded in buds. A note on moving roses. Roses which are grafted on Dr. Huey is less forgiving in moving. Dr. Huey is a long stick, and it's easy to break the tiny roots at the end. I moved knock-outs grafted on Dr. Huey twice before. Both time they lost all their leaves, and took at least 3 months to get back to normal. With own-root, it's so much easier to move: The roots are cluster: wide & shallow, rather than a long & deep stick like Dr. Huey. I moved at least 10 own-roots for the past 4 years: They recuperate quickly, lose zero leaves, IF THE ORIGINAL SOIL IS LOOSE & FLUFFY, then moving is zero stress. If the original soil is compact, digging them up caused many roots to be broken.

Below is the info. that Floweraremusic (zone 5) in Washington gave on her 2020 winter-survival. She has alkaline clay with rocks at bottom like mine & less snow in winter: "My hardiest roses are the Canadians. John Davis, John Cabot, Wm. Baffin, Morden Sunrise, Morden Blush and Morden Centennial, Victorian Memory aka Isabelle Skinner, also a Canadian rose. All these only have tiny bit of tip damage and bloom a lot with no special care. Also, my Hybrid Perpetuals only have tip damage after winter. Magna Charta, Mrs. John Laing, Black Prince and Marchesa Buccella. The only negative is they don’t have long enough cutting stems. All my Austins are very hardy. The one I just can not grow is Jude. Leonardo da Vinci is super hardy and always healthy. Quietness comes through winter very well. Even Rouge Royale survives beautifully. Cinderella Fairy Tale is very hardy. Gruss an Aachen also. Ballerina and Marjorie Fair are both hardy. Poseidon, Princess Charlene de Monaco and Crazy Love didn’t do as well as I’d hoped. The surprise losses this year are Quicksilver, and Dames de Chenonceau who is left with only 1 cane. Versigny is also reduced down to almost nothing. This was a mild winter with very little snow. " Floweraremusic (zone 5). From StrawChicago (zone 5a with hard black-gumbo alkaline clay & less snow but with freezing rain in winter). Versigny didn't survive winter either. So I lost Versigny TWICE. Besides Versigny, other wimpy own-root roses that don't survive winter well: Paul Neyron, Anna's Promise, Pink Peace (own-root died 1st winter, but grafted-Pink Peace survives many winter), Elantyne, Jude the Obscure, Young Lycidas (bought as grafted-on-Dr.Huey, now with only one cane), Mary Daly, and many floribundas don't survive my zone 5a: Pink Chiffon, Sheila's perfume, King Arthur, Deep Purple, Shocking blue, Honey Bouquet (survived 1 winter). Polka Climber (survived 1 winter), Cloutilde Soupert (died twice on me). Sutter's Gold didn't survive winter, same with many fragrant mini-roses from Burlington nursery. Below are my hardy OWN-ROOT roses in my zone 5a alkaline clay, only Double Delight, Young Lycidas and Lavender Crush are grafted-on-Dr.Huey. Bold-faced are the very vigorous ones: Own-roots with 3 feet of green canes: Carding Mill (since 2012), Princess Charlene of Monaco, Duchess de Rohan, Crown Princess Magareta (since 2012), Zepherine Drouhin, Lady of Shalott, James Galway, Lavender Crush, Queen of Sweden (gave away but very hardy), Poseidon (right below the rain-spout, dug down to 2.5 feet), Scepter'd Isle (very big & hardy own-root but gave that away with its lousy scent). Own-roots with 2 feet of green canes: La Reine (many winters), Blue Mist (since 2012), Prairie Harvest (since 2014), Mary Magdalene (since 2011), Evelyn (since 2012), Radio Times (since 2011), Pat Austin (since 2011), Christopher Marlowe (since 2011), Golden Celebration (since 2011), Lilian Austin (gave away but very hardy), the Squire, the Dark Lady, Wise Portia survived 4 winters but died in poor drainage clay, Dee-lish (since 2015), Twilight Zone (since 2016), William Shakespeare. 2000 (since 2011), Comte de Chambord (since 2012), Princess Anne, Sweet Mademoiselles, Aloha climber, Orchid Romance, Bohemian Rhapsody, Marie Pavie, Lagerfeld (since 2017), Frederic Mistral survived 2 winters but died when I didn't winter-protect with leaves, Sonia Rykiel (survived 3 winters) but died in freezing rain winter, same with 1/4 of the street-trees in my neighborhood, Excellenz von Shubert (since 2013), Own-roots with less than 1 foot of green canes: Gina's rose, Tchaikosky (since 2015), Cornelia (since 2018), Bolero (few winters), Peter Mayle, Sharifa Asma, Neil Diamond, Amber Queen, A Shopshire Lad, Strike it Rich, Old Port (since 2012), Veteran's Honor (many winters), Double Delight (grafted on Dr.Huey), Savannah, Tess of d'Uberville, Gene Boerner (since 2014), thornless Yves Seedling (since 2013), Stephen big Purple (since 2012), Louise Este, Mirandy, Crimson Glory, Liv Tyler survived 1 winter but needs winter-protection, Rouge Royal (bought last year with no winter-protection). Annie L. McDowell (survived 2 winters but needs a wet-spot since it's almost thornless), Nahema (survived 1 winter then died during freezing-rain winter), same with Eyes-for-you (drought-tolerant and doesn't like freezing wet winter), Souvenir du President Lincoln, Madame Issac Pererie and Madame Earnest Calvat, Firefighter (survived 2 winters) but died since it's next to tree. Bayes Blueberry (survived many winters but I gave away), Charles Darwin (gave away since it fades badly), Arthur Bell (since 2012 & killed it since I don't like the flowers). StrawChicago.

@BenT (NorCal 9B Sunset 14), your LC blooms are certainly beautiful. I wish mine would be like that. Mine only look good when the blooms just opening. Then the color is quickly washed out and does not look attractive. This is only spring and the weather is mostly pleasant. I can understand that @PDXRobertZ8 had to remove it. Mine does not take a prime spot.