Perennial Cover Crop Experiences?

Hi fellow Permies!  I'm conducting a cover crop experiment in my orchard this year and would love to hear any experiences you may have had with perennial cover crops.  I live in the Santa Cruz mountains, zone 9b, full sun, growing in sandy loam soil.  This season I'm going to test out bird's foot trefoil, perennial sweet pea, Siberian pea shrubs, goumi shrubs, and perennial lupines.  I've tried clover in the past, but we have a ton of gopher activity on our mountain, and found that this caused a huge number of gophers to move into our orchard.  Yikes!

My thought is that a perennial groundcover could be periodically mowed or sheared to release nitrogen into the soil throughout the season.  Do any of you have any thoughts or experience with this?  I welcome your ideas...

Hi Christy, that makes sense. By cutting the cover crops you should be adding the nitrogen in the cut tops plus there should be some corresponding dieback of root systems that will also release nutrients.

I am planning to do something similar with cover crops in zone 8 but want to retain the option of grazing livestock in the tree alleys. So there is some overlap in our plant lists but I will be avoiding some of the plants you mentioned as being incompatible with livestock. Will be leaning more toward clover as I don't have the gopher problem you mentioned. For certain grazers I would be cautious about clover but my goats seem to digest it ok.

Good idea trying a mix. Lotus (trefoil) is great but goes dormant in winter here and I suspect will do the same in your climate, so having some cool-season alternatives like lupines will keep the growth going year round.

I have used perennial sweet pea as a landscape element to complement a split rail fence on the berm surrounding a business. Makes long vines with attractive blooms. With seed maturity and summer drought the vines may die back and regrow from the roots with the next rain season. Vines with unopened browning pods  can be moved to seed a new location. May combine well with the upright nature of the lupin. Both prefer a mulch/ground litter for germination. I have a vinca minor ground cover around my 100 year old trees but how it suffers during summer drought indicates it may not work well for you. Evening primrose and holly hocks come up in my orchard and are biennial, grow tall and are often eaten by the deer which reduces the pressure on the tree leaves.

Thanks for so many great ideas!  I'll let you know how my experiments go this year.  :)