We do not have root knot nematodes so I have no idea how they may or may not affect flowers. I have to add that I am willing to bet that your wife will be delighted with the surprise of you adding flowers to the garden.

Zinnias work great in fairly hot and dry weather so I use them a lot. They are pretty, attract tons of butterflies and can be cut endlessly for bouquets. With the cutting types of zinnias, it seems like the more you cut them, the more they grow. Cosmos is about the same, and they have them in heights varying from about 1' tall to 4' or taller, so there's a cosmos for every spot. Moss rose is another one I like, though sometimes the voles eat them in July and August in order to get the moisture. Moss rose is very drought-tolerant. Verbena bonariensis (which is a tall verbena that is incredibly drought tolerant) reseeds in my garden and is pretty carefree. You do have to deadhead the flower stalks occasionally. I personally tend to avoid marigolds because in my garden they are spider mite magnets. Celosias are pretty and are fairly drought tolerant. Annual salvias come in shades of red, pink, white, purple, orange and blue and are very attractive. If you want to plant perennials instead of annuals, you cannot go wrong with purple coneflowers, (and they come in other colors than purple nowadays) and coreopsis. Autumn sage is another perennial that is almost shrub-like. You can get autumn sage with various colors of flowers. The various ones I have bloom in shades of red, raspberry and white. One has flowers that are red and white. You also could grow herbs which could be dual purpose. Many herbs do flower and also have leaves, stems or flowers that are edible. When they flower, they tend to be very attractive to bees and other beneficial insects. In my garden, I grow a lot of herbs, including borage, basil, lemon balm, catmint, catnip, dill, fennel, bronze fennel, tansy, silver tansy, comfrey, pineapple sage, rosemary, and sage. I have slow-draining clay (it even drains fairly slow despite being well-amended) so I avoid the herbs and flowers that need really well-drained soil. Hope this helps.

Dawn has listed several good ones. I love zinnias! They're so easy and come in so many different colors and flower head shapes. My latest favorites have big flower heads. Burpees carries two I really like: Giant Flowered Mixed Colors and White Wedding.

I buy other brands that are cheaper and can usually find these at Wal-Mart, Lowe's, etc.

Good luck and good for you, planting lovelies for your lovely wife!

Carol

I always put marigolds around my veggies. Just because they are so bright. I'm not sure if they are good or not for veggies, but I like them. Once planted, they seem to come up in various places on their own the following years. Nasturtiums! Laura Bush Petunias? Dawn gave me one at the Spring Fling. Love it AND it smelled nice. Also, my door prize (at the SF) included a package of them. Oh, and echinacea too.

Your climate is extremely different from mine, so I will refrain from making and direct, recommendations. Still, I thought you might find this interesting. Some of the other responders have mentioned plants that make excellent companion plants for vegetables. You mentioned that you have every pest on Earth in your garden, so I thought this might be beneficial to you. I originally read about this in an old Rodale's book that my sister gave me, so I can support this link.

Companion Planting

You also might consider planting some edible flowers, and some of those have been mentioned as well. That might make your wife happy. I'm a wife and it would make me happy! Borage, Dianthus, Calendula, Pansies (probably don't do well where you're at), etc. are all edible and attractive. Here are a few that might work for you-

Edible Flowers

I planted Elbon Rye as a cover crop last fall to manage nematodes. Even if it doesn't kill the nematodes, it has been a beautiful, rich green all winter, untouched by weather. We have clipped it to feed the chickens, too. I got mine at Holman Seed Farm in Collinsville, but I'm guessing any feed store would have it.

Dawn gave you a great list. I would add gaillardia (blanket flower), it laughs at our weather.

Kahnke Brothers Tree Farm, you'd be surprised that, during several winters, I've had pansies carry over from fall planting into spring. But, oh, when that dry, hot Oklahoma weather comes, they have to kiss us good-bye!

Carol

Very interesting! I know so little about growing things in southern zones. Thank you for the info!

I like Dawn's mention of flowering herbs. . . that way you'd be satisfying your inclination to eat what you grow, AND have flowers for your poor long-suffering wife! :) Calendulas, of course sprang to mind first.

I planted marigolds and nasturtiums last year. The nasturtiums seems to help a bit with my squash bug problem until I was out of town for too long and the bugs took over. The nasturtium flowers and leaves are edible and yummy in salads!

thank you so much I can name many varieties of different vegetables But I am in the books trying to understand what you all are talking about. This is a new world thanks again. Is there a marigold that is suppose to help with nematodes

I started with zinnias. They are easy colorful and lots of different sizes. And you can save the seeds for next year. AND cut them for your wife for bouquets in the house. Win win win