Question
QUESTION: I have a hillside that is quite steep.  It's about 70' long by 12' deep at the ends and 22' deep in the middle.  It slopes down in a CONVEX manner to a flat lawn.  I tore out some overgrown euonymus and had red clay brought in to reduce the very steep slope.  I probably should have had more fill brought in but was trying to keep the cost as low as possible.  I have planted 30 small shrubs and 4 large flat rocks on the hillside and bought 50 bales of pine needles to mulch the hillside.  We had moderately heavy rains last week and there was a fair amount of fine clay deposited at at the bottom of the hill.  Now I'm wondering if I need to put down a landscaping fabric to help stop clay erosion and keep the pine needles from sliding down the slope (which I have not yet put down, by the way).  I've priced jute fabric and excelsior blanket (about the same) and wonder which would be best.  Also wondering if I chose the right mulch or would some other mulch be better?  Have priced bagged mulch here, which would be easier getting up the slope to spread  and find cypress mulch to be the cheapest.  What do you think of it?  How about putting down a thin layer of it and then putting down the pine needles, which I already have over the top of the cypress mulch?  If it sounds like I've made a lot of decisions without doing my homework first, that's because I did.  Now I'm stuck with the red clay hill and need to do something to keep it in place.

Another question:  If I were to plant English ivy on the hill, my wife says this will choke out the shrubs I've planted.   Is this true?

ANSWER: Hey, Paul.

Steep slopes can be both fun and exasperating to work with. I personally find them fun.

The fact that you found red clay, have moderate rains, and were able to buy 50 bales of pine needles tells me that you're probably not in the Southwest where steep hillsides are, in my opinion, easier to work with and landscape because of the lack of rain.

So, first, I would suggest some landscaping fabric to hold the clay in place while the plants are developing roots and ground cover to do the same. It shouldn't matter what type you buy, but make sure that it is biodegradable. I find it amazing that companies make non-biodegradable landscape fabric, but maybe that's just me.

The type of mulch is going to be personal preference. Pine needles are an excellent choice if you are also looking for simple, easy weed control. Virtually nothing will grow in pine needles, which is why I have never had pine trees in my landscapes except at the Client's absolute insistence.

I think it's probably not necessary to put down any other mulch under the pine needles, as long as you do have enough pine needles to create a good half-inch to one-inch layer.

One thing that you might consider to help you in the whole process, and with maintenance later on, is to create at least one terraced pathway directly through the center of the hillside from side to side. That will make it easier for you to work up there in the middle of the hillside. Once you're finished, if you don't like the pathway, then you can fill it in. I think that you'll be inclined to keep it, though.

So, I don't think you're "stuck with the red clay," you just have to complete all your homework and determine what landscape fabric is best, most pleasing to you, and fits into your budget.

I personally don't like English ivy on hillsides because it grows too fast and overgrows anything in its way. However, if you want it, that terraced pathway can help you keep it under control through pruning. So, with the English ivy, I agree with your wife. Left on it's own, the English ivy can choke out anything else.

By the way, I give you and your wife an A on your homework.

Feel free to follow up in you need to. I hope I've provided some help.

---------- FOLLOW-UP ----------

QUESTION: In researching erosion control on the net I've seen references to installing landscape fabric OVER the mulch.  What are the advantages and disadvantages of doing this?

I've mentioned jute and excelsior blankets as landscape fabrics.  Which do you think would be best on a red clay surface (I live in Hendersonville, NC) with pine straw mulch?  Would one or the other last longer, i.e. not degrade as quickly?

Answer
Hey, Paul.

Most good landscape fabrics, such as those you are considering, are very coarse and uneven. The reason for that is so that they will stick to the surface. That same coarseness results in any mulch sticking quite well to them, and pine needles should stick particularly well. Consequently, I know of no specific advantages or disadvantages of installing landscape fabric over or under the mulch other than pure aesthetics. I personally think that landscape fabric looks artificial, possibly because it is artificially created, so I tend to put the mulch on top of the fabric since it looks more natural that way.

I believe the excelsior will last longer than the jute since many excelsiors have some plastic added to them for stabilization purposes. In North Carolina, you might be more successful with the excelsior since you get more rain there. We use mostly jute here in San Diego and Southern California because we need it to degrade quicker due to our lack of rainfall. I used excelsior mostly in East Texas and Louisiana.