You don't have to test for nematodes. You have them. We all have them. They will eventually kill your roses if they aren't grafted, and even roses grafted onto the best rootstocks will die eventually. This is a technique for planting that will hold them off for awhile, but not forever. It really is best to plant Fortuniana grafted roses in FL, though, and even they don't live forever. Your own-root roses have about 5 years before they will die. I hate to be harsh, but that's my experience and that of many northerners who move down here and plant their favorite northern roses on their own roots. Dig a hole 3x the diameter of the pot you're transplanting from, or about 20 inches for bare roots. Dig it 3 inches deeper than you want the plant to sit. Fill the bottom three inches with straight organic peat, put your rose in and add peat until you get it to the right height, then fill the entire rest of the hole with organic peat. (Organic peat is not the same as peat moss). Nematodes hate organic matter, so this will keep them away from the roots, but not forever. It will stave them off for a few years, though, until the organic peat breaks down. I don't know any more about growing roses, just this. I'm sure someone will come along and help you who knows more. I do know some OGRs (Old Garden Roses) will grow on their own roots here.

I have only two Austins (Golden Celebration and Darcey Bussell) on DH roots and they are planted in a spot with Sycamore root competition, which is probably the only reason I can grow them there. They both have spotless foliage. I am inland quite a bit and at 1800ft. We do get May-Gray and June-Gloom, but it burns off by between 10AM and noon. I have Paul Neyron, which is a rust bucket right next to Rein de Violettes with pristine foliage, never a spot of rust or mildew. All my Teas get a little mildew except Monsieur Tillier. My Lady of Shallot is on her own roots and does very well with perfect foliage. I really want Evelyn but now I am a little scared by the 12 foot canes jerijen mentions. I have Star of the Republic with only a couple blooms that have been scented and I really want scent in my roses so thinking about replacing with Evelyn. But will give SotR a 3rd year to see if those blooms get consistent scent. The 3 or so blooms that I caught with some scent were an amazing strong lemony fragrance. Maybe just doesn't give scent in the heat? I also have James Gallway on its own roots and near Golden Celebration but further from the sycamore. It is establishing more slowly and not behaving like a climber at all yet, next year with be year 3 so maybe I'll get long canes in the Spring.

UPDATE for 2024: High Country Roses add lots of Autin own-roots to their inventory (sold out to those who ordered early): Jude the Obscure, The Prince, Ambridge Rose, Abraham Darby, W.S. 2000, Othello, Carding Mill, Sophy's Rose, Evelyn, The Dark Lady, Wise Portia, Charles Darwin, Emanuel, Sharifa Asma, Charles Austin, Eglantyne, Lucettta, Molineux, Graham Thomas, Tamora, Noble Antony, Benjamin Britten, Gertrude Jekyll, Mary Rose, Heritage, Tess of d'Urberville and many others. I got my W.S. 2000 from High Country Roses back in 2011. I should had ordered from High Country Roses back in Nov. 2023, it's only $23.95 per own-root Austin. High Country Roses in CO now ships roses to Canada.

Trying to grow "disposable gift" miniatures is an exercise in futility, especially in a colder climate. Those things were bred for ONE PURPOSE: to grow fast in a greenhouse environment, bloom quickly and easily, and that's all. They were not bred for hardiness, nor garden performance. Do yourself a favor and buy some miniatures bred for growing in the garden. The named varieties are excellent. Get a plant of 'Rise 'N' Shine', or 'Sequoia Ruby', or 'Sweet Chariot' and you'll see a huge difference in their garden performance. RE Shipping: charging $9.99 to ship a plant is cheap. Have you been to the Post Office recently? Most packages bigger than a VHS box cost at least $10. to ship anywhere. Its just how it is. Its not as if the merchant is trying to rip you off with bloated shipping prices.