Of course, pretty much anything works with firewblossom or daybloom, but what works well with waterleaf and especially deathweed?

Are you asking about aesthetics, or about the mechanics on how to best farm those herbs?

I was under the impression that something could either grow with a wall or not. I wasn't aware the type of wall mattered.

That's why the only thing I farm is Glowing Mushrooms.

Utility, mostly.

I'm having a tough time seeing the difference between mature and baby deathweed, for instance. Yes, I know its bigger, but I hate having to stop and put my glasses on to distinguish between them. The rest are obvious against pretty much every background, even without my glasses, though waterleaf can be tough if I'm playing in a sunny spot.

A pure color, without a lot of variation, preferably light colored, would be ideal, I should think. Or maybe the pale blue of deathweed would stand out against a dark solid color, too?

Just use the Staff of Regrowth, it only harvests fully grown plants.

As of 1.3.0.1

Oh, thats what you mean. You are right, some herbs are difficult to distinguish.
Both Deathweed and Waterleaf have specific blooming conditions. Deathweed blooms only during a Blood Moon, and, as far as i know, since 1.3, also during a full moon. When it is blooming it emits a faint glow, so it's best to plant it in a dark area.
Waterleaf blooms only when it is raining. I think it does not glow, but with a bright background, blooming Waterleaf is easy to see.

Unkalibriert's tip of using a Staff of Regrowth is great, that item is now usefull since 1.3 :) Also it's a lot easier to find. Look for giant trees in the underground Jungle, similar to the giant trees on the Surface. If they are hollow, they will have a chest at the bottom, with a very high chance for a Staff.
If you use the Staff to harvest, it will only destroy blooming herbs, and you will even get more seeds and herbs, than ordinary harvesting with a pickaxe. That, and the addition of the new alchemy table, water bottles stacking to 999 and the new planter boxes sold by the dryad, makes alchemy much more viable now.

I've been using the staff of regrowth for some time now, and never noticed that it did not harvest immature plants. I've been carefully avoiding them.

Great tip!

Thanks!