What type of soil do you have? Specifically, do you know what your percentages of clay, silt, and sand are? If not, maybe think of doing a soil composition test with a preserving jar:

https://www.youtube.com/watch?v=3g2nro1EWGE

My guess is that your berm soil is drying out in the top layers, and the perennial plants with thin surface roots are really stressed out. A three to four-inch layer of mulch will probably fix this entirely.

Some of your plants are better adapted ,replace those that aren't with more that are.

@Mathis You might want to consider editing your name to include your region and your plant zone. That's a convention that is followed on Gardenweb and saves questions in many situations.

Compost is always my first choice for mulch.

Compost is a great mulch. It won't match your current wood mulch, but it will be better feed for your plants.

I like gardengals48 answer. Very helpful thank you so much!

Would love to know which you went with in the end? I have added topsoil to my flower beds and was hoping to use that as mulch this year but we have had inundating rains and the soil just gets everywhere! I’m curious how one handles that.

Wondering if compost would be a superior alternative to bark mulch for plants that dislike moisture (lavendar, etc.), since it drains well.

No. Compost is much more water retentive than bark mulch. I would never mulch lavender with compost.

@gardengal48 (PNW Z8/9) Although I will say my four-plus inches of composted bark mulch does retain a heck of a lot of moisture. But it's a very high-humidity moisture, not actually liquid water. It feels like something a plant would love.

@HU-918119203 Gravel, pine needles, or coarse organic mulch would work for lavender. But there may be some misunderstanding of the role of mulch. Mulch is an insulator that prevents the first two to three inches of moisture from evaporating at the top of the actual soil surface. It is not a substitute for well-drained soil.

Lavender likes well-drained soil, so with or without mulch, you need to be more concerned with the soil mix and the level of the water table than with the type of mulch.

Compost mulch is also a very effective (and attractive) weed suppressor, and a castings-producing-worm attractor. In addition to using compost for almost all of my mulches, I depend on it for most of my fertilization. I might supplement it with nitrogen amendments---like alfalfa or blood meal.

I guess my confusion re: compost is that I often see it recommended as a soil amendment to improve drainage (and have successfully used it as such in my garden). Bark mulch, by contrast, is recommended to hold moisture at the surface.

Understood re: the role of mulch, but for lavender I've often seen mulching dissuaded (other than with something like gravel which would not work for me).

Both products - compost and bark - will retain moisture at the soil surface. Actually, ANY organic mulch will do the same. The difference comes with the moisture content of the product itself. Because of the source and the chemical composition, bark mulches are dry. In fact, other than fresh arborist's wood chips, all wood based mulches are quite dry.

OTOH, compost is wet. Even finished compost is around 45% water and active but unfinished compost can be as much as 60%.

This is easily confirmed by their relative weights. Compost is wet and heavy and weighs around 1250 lb/cubic yard. Bark and most other wood mulches are dryer and lighter, at somewhere around 500-800 lb/cubic yard.

@HU-918119203 You still haven't told us what is the composition of the soil that the lavender is planted in.

Well, I don't have an issue with or question about my soil. I was asking about mulching with traditional bark vs compost. I'm still not really understanding the answer, as the starting moisture content of bark vs compost doesn't necessarily dictate how much moisture either holds in the soil in situ.

Any mulch - even rock or gravel mulches - will slow evaporation and help to maintain soil moisture but I am not aware of any studies that have calculated any differences between the amount of soil moisture maintained and for how long between various mulch types. Since all mulches are applied with the similar intent - weed suppression, soil moisture conservation and moderation of soil temperatures - it then comes down to the type of mulch itself and how appropriate it may be to the type of plants you are growing. Heavier, wet mulches like compost may be great for the majority of plants that prefer consistent soil moisture but not at all appropriate for those that prefer very lean, even rocky but fast draining soils, like lavender and other xeric plants.

It depends on where you live. Where I live, no one uses compost as mulch. It's too hot and dry in the summer. It would just create a new top layer, where roots would grow and then quickly dry out. It wouldn't keep the soil moist or keep weeds at bay. it would actually make moisture issues worse since compost has a lower cec than our native silty clay soil. Compost is only used and sold as a soil amendment. Mulch is always assumed to be shredded hardwood where I live. If you live in an area that is typically cool and moist like the pacific northwest, compost may make a better mulch.

As I see it the problem here is rabbit holes and wild geese. Without knowing a single thing about OP's soil and what's planted in it, several wild geese have been chased down rabbit holes.

@HU-918119203 No, you do have an issue with your soil. The requirement that Lavender has for well drained material is a requirement for the SOIL not the mulch. Any good compost or bark mulch is probably going to be fine as a mulch for Lavender. But we should confirm what your soil composition is and whether that creates any issues for Lavender, and that is actually the more logical and important application of your concern than obsessing about the mulch.

A lot of us garden intuitively, westes. I might test my soil if I had problems, but I generally observe my plants and alter their care according to the way they falter. Soil tests are interesting and informative, but certainly not mandatory. A plant that doesn't like it moist is not going to like a moist mulch---no matter the soil underneath.

Charles Kidder, I can't imagine any climate where a compost mulch couldn't be recommended. People nowadays don't seem to know about using compost as a mulch, because in the 70s all of a sudden everybody embraced the wood industry's successful marketing of wood chip mulches, resulting in a total hijacking of the term 'mulch'. I never saw that fast food style wood mulch until I actually saw my first MacDonalds. When I was a kid, my father (who came from hot Oklahoma) called our compost pile the 'mulch' pile.

I do think wood chip mulches are fine if you can't get compost---better than a stick in the eye.

@annpat I never told him to test his soil. And I don't need to know that he has 56.5433% sand either. But does he have sandy loam soil that has problems holding water? Does he have a hard clay soil? Is the soil acidic? If he knows absolutely nothing about his soil, then maybe a little investigation of the soil mix would produce as much or more benefit as looking at the mulch.

If he has the lavender planted in a hard clay loam soil in an area that floods, it won't matter what kind of mulch he uses.