Rock mulch

A few years ago I read that the cypress tree swamps were being clear cut for mulch. I haven’t purchased mulch since. In the areas under trees I let the leaves and pine needle accumulate. In the other areas I turned to rock.

A garden with out mulch in Houston is a doomed garden. With out mulch the summer sun will bake every thing to a crisp or a heave downpour will wash away your plants and soil.

Rock mulch builds up heat during the day, slowly releases it at night keeping the soil and plants at more moderate temperatures. It made a noticeable difference during the late frost we had in 2019.

It lets water run through to the soil under the plants and slows evaporation, prevents erosion and most important – it doesn’t need to be replaced every year.

Little did I know that the people on Easter Island used rocks to keep their gardens going as the environment deteriorated. The technical term is Lithic-Mulch, which translates to …. rock mulch.

There are many benefits to rock mulch, more so in dry areas. Previous cultures used it in New Mexico and Arizona. If you’ve live in Houston long you know we switch between decades of drought and decades of downpours. Rock mulch works for both.

Sometimes holes are dug, lined with rocks or small walls built around plants. This protects the plants from strong winds and provides a little shade. Another option is a layer of rocks is placed over the soil the same as is done with mulch.

A taller pile of rocks on the south side of a plant (Talus garlands) can protect young trees or shrubs. The pile of rocks provides shade, condenses water at night to add to soil, keeps weeds under control, keeps critters from digging and provides wind protection.

The Nature, History, and Distribution of Lithic Mulch Agriculture
Easter Islands Ancient Gardening Practices
Growing Fruit Trees in Drought Areas

Annual National Garden Survey has been released

The annual National Gardening Survey finds the proportion of older gardeners is holding steady (35%) but younger households reached an all-time high in gardening participation. “From small beginnings with a succulent here and a houseplant there, the under 35s are now truly engaged in the full range of gardening activities.” says industry analyst Ian Baldwin, who participated in the survey.

Overall, American gardeners reported spending a record $47.8 billion on lawn and garden retail sales, the highest ever, with a record average household spend of $503 – up nearly $100 over the previous year.

Container gardening and landscaping set new highs in gardening sales, too. “More and more consumers are choosing not to dig holes in their leisure times. If they have the finances, they are investing in raised beds,” says Baldwin.

Indoor gardening is also making a big comeback with 30% of all households buying at least one houseplant. Baldwin says it harkens back to the ‘70’s and ‘80s, “when no home was complete without various sizes and shapes of non-flowering plants in pots or macramé hangers acting as cheap room dividers.”

Power Point Summary
Full Survey

Species, Variety, Cultivar


  • Angiosperms: Flowering plants
  • Gymnosperms: Conifers, cycads, allies
  • Pteridophytes: Ferns
  • Bryophytes: Mosses and liverworts
  • Families:

  • Currently 642 families
  • Genus:

  • Currently 17,020
  • Group of related plants
  • Origin, type, group
  • Species:

  • Genus name + specific feature that makes it different than other plants in Genus
  • Breeds true from seeds or cloning
  • The largest group in which two parents can create fertile offspring
  • Variety:

  • Usually occurs in nature and have same characteristics of parents
  • Seeds from varieties usually have same characteristics
  • Always written in lower case
  • Hybrid:

  • Crosses between species or different parentage in the species
  • Seeds rarely breed true
  • Cultivar:

  • Cultivated variety, created by humans. Some are mutations, some are hybrids of two plants.
  • Seeds don’t usually breed true, propagation by cloning is needed ( from cuttings, tissue culture )
  • First letter of a cultivar is capitalized
  • Heirloom:

  • Varieties found in nature for at least 50 years
  • The Plant List on going list of all known plant species

    Invading lizards from Cuba

    Cuban brown anole have been moving in and pushing the native green anoles out. If you see any take a few minutes to fill out the survey for the SW Center for Herpetological Research (link below)

    Houston Arboretum, A new lizard in town

    Southwestern Center for Herpetological Research, Survey on sitings of Cuban Brown Anole

    The Green Anole, Your Resident Backyard Lizard, Is Being Pushed Out By Its Uglier Cousin

    Giant tree forests need 59″ rain per year to form


    Tree canopies come in two main heights ~82′ and 131′. They form in tropical and temperate regions but only if the yearly rainfall is consistently 59″ or more

    Rainforests are among the most charismatic as well as the most endangered ecosystems of the world. However, whereas the effects of climate change on tropical forests resilience is a focus of intense research,the conditions for their equally impressive temperate counterparts remain poorly understood,and it remains unclear whether tropical and temperate rainforests have fundamental similarities or not.Here we use new global data from high precision laser altimetry equipment on satellites to reveal for the first time that across climate zones ‘giant forests’ are a distinct and universal phenomenon, reflected in a separate mode of canopy height (~40m) world-wide. Occurrence of these giant forests (cut-off height > 25 m) is negatively correlated to variability in rainfall and temperature. We also demonstrate that their distribution is sharply limited to situations with a mean annual precipitation above a threshold of 1500 mm that is surprisingly universal across tropical and temperate climates. The total area with such precipitation levels is projected to increase by ~4 million km2globally. Our results thus imply that strategic management could in principle facilitate the expansion of giant forests, securing critically endangered biodiversity as well as carbon storage in selected regions

    A Global Climate Niche forGiant Trees