Most everyone has some sort of a long lens – 35-70 or 70-200 will even work. The key is to see how close to the wildflower you can get and still focus. The closer you can get, the greater the background will drop off. Call it Bokah or soft background but getting close is the key. The longer the lens the more bokah you can get.
Extension tubes to solve a problem.
If you can’t get close enough insert an extension tube between the lens and Camera Body. Extension tubes have come down in price. Check B&H photo, Adarama, or Hunts Photo. KEH also sometimes carries used tubes. Make sure they have electronic hook ups, or if you shoot manually for these kind of close ups it will not matter.
Extension tubes do not have any glass in them to degrade an image, unlike a telephoto lens. They essentially only move your camera sensor or film further away from the subject, thus providing extra magnification. Extension tubes can be used on any lenses. The only caveat is the “mm width” of the tube must be smaller than the focal length of the lens.
If there is a lot of background in the image, you may be able to cut down the effect by using the contrast slider in post production.
Don’t have long lens?
Check with KEH or B&H Used section. The Nikon 300mm 4.5 EDIF lens I paid $800 for 30 years ago, now sells, on the secondary market, for less than $200. I still have mine, have to use it on “manual,” but it is a very sharp lens and produces killer Bokeh as well as cuts down edge distractions. I use it with an adapter on my Sony mirrorless.