Hi Ellen, welcome to the forum!
Overall, I'd say you got pretty good results from the kit zoom, about as much as you can expect from a non-macro lens. The B+W and last shot are especially nice, fine work!
# 1 and 2 are composed and photographed well, but the distracting background elements don't help. On the first one, if you crouched down and put a completely green b/g behind the plant, no clash of shapes and colors.
Same for # 2, move a bit right or left and eliminate the gray vertical shape (wood?) and slanting diagonals, it could be better overall.
Hope you don't mind my mini-critique! I started a thread here on creative backgrounds, it may provide some examples.
I have the 18-55mm W/R, and have used it for 'close-ups' in a pinch. By stopping down to (at least) f/8.0 and not extending to a full 55mm (about 50mm seems OK) you eliminate 2 of the weaker areas of this lens; shooting wide-open and softness at full zoom.
But, you're still better off with a dedicated macro lens, no doubt.
One low-cost way to try 'semi' macro is to find an a Pentax F 35-70mm f/3.5-4.5 on the used market, about $50 USD. This has a macro function at the 70mm end that works as well, if not better, than any 'Zoom with macro' function I've seen. It's also a dandy short zoom, there's a thread for that lens, too.
Also, the FA 100mm f/3.5 Macro (Pentax, Cosina and a couple other versions, all the same lens) sell for about $100-150 USD, used. Just make sure it's a K-mount!
https://www.pentaxforums.com/lensreviews/SMC-Pentax-FA-100mm-F3.5-Macro-Lens.html
Hopefully, as this Macro Forum gets rolling, we'll see more recommendations for other lenses.
Thanks for posting!
Ron