Ground Cover Between Stones

What can we plant between stones?

Many of the best looking flagstone pathway and patio projects utilize low growing ground cover between stones. In some situations (like our Gallatin Woods Flagstone Project), stones are set tight and the joints are simply filled with polymeric joint sand. Today we will ignore the latter and focus on natural stone flagstone with wider joints that can be planted for a more naturalistic effect.

There are a few preferred ground cover species for use between stones in Garrett County, Maryland. I have listed them below. Make sure the specific cultivar you choose is rated for USDA zone 4 and zone 5. You can do a google image search for any of the species below.  Another good visual resource is this site here.

  • Creeping Thyme, Thymus Serpyllum (seed available online)
  • Blue Star Creeper, Laurentia axillaris ‘Blue Stars’
  • Gold Creeping Jenny, Lysimachia nummularia ‘Aurea’
  • Lamium, Lamium maculatum
  • Ajuga, Aguga reptans
  • Scotch & Irish Moss, Sagina subulata
  • Baby Tears Stonecrop, Sedum album ‘Chloroticum’

Use Thick Flagstone.

Thicker flagstone means more room for quality planting soil and your ground cover roots. Roots won’t be able to “root in” to the compacted gravel base, so we must provide a few inches of planting medium (soil). Make sure the stones that you are using are minimum 2.5 inches thick. Local quarries in Garrett County are commonly pulling out flat stones that meet or exceed this thickness requirement. The extra thickness adds weight and you should expect to experience extreme heavy lifting when moving them around by hand. We purchase much stone from Green Things Stone located near Red House (they ship to to the entire east coast). Ron with Green Things Stone will have the thick stuff. Cost typically runs $400 per ton plus tax… excluding delivery. Keep in mind the extra thickness adds weight and cost quickly as stone is sold by the ton.

Prepare Your Base.

Next consider how you will install your stones. Do you plan to install them on top of a prepared and compacted crushed limestone base? Or do you simply want to position the stones in the native soil? For longevity and lower maintenance, we always recommend installing the stone on a 4-8″ thick compacted base. However, if the stones are big enough, it will allow you some more leeway with the base. Either way, the next step is to excavate and prepare your base. When you begin to lay out the stones consider the shapes and how they best fit together. You don’t want to cut with the saw or chisel any more than you have to. 3″ thick stones are extremely hard to shape, lay out your stone and stand back to look things over. You want to utilize the natural shape of the stones to maximize efficiency when putting the puzzle together. This is the step where most people struggle. Unless you have the proper eye and experience, picking out stones that naturally fit together properly will be difficult. Position the stones and level them appropriately from stone to stone. Natural Stone varies in thickness, so you will have to spend some time leveling and re-leveling the stones to get it right. Try not to have trip steps or uneven stones…. again you want things level from edge to edge.

Allow Up To 3 Inches Between Stones.

When setting the stones allow up to 3 inches between stones. The end result will be a void that is roughly 3″ deep with good soil and up to 3″ wide. Purchase your choice of ground cover and install between the stones. Not many ground cover plants will work in such a small space, stick to the list above.

Suggested Care.

Keep things moist with an occasional light mist from the water hose for the first 2 weeks. Once the plants take off on their own they should require little or no maintenance. You will need to take a little time to pull weeds by hand until the ground covers really start to spread and take over. And finally, this effect is best achieved on a patio or walkway that doesn’t see daily heavy use. You will see the best effect on weekend patios or homes where foot traffic is limited. If the area is going to see heavy and daily use… then perhaps consider tighter joints and bypass the planted joints.

We offer design and installation for any natural stone surface you can think of. Give us a call if we can help.

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