the show

San Antonio Garden Conservancy Tour 2017

air date: September 30, 2017

See how San Antonio gardeners keep the style going despite dry times. Garden Conservancy Regional Representative Shirley Fox previews the 2017 Open Days gardens. On tour, Mary and Lewis Fisher dumped the lawn for native and adapted plants that grow awareness of the past to impact the future. Daphne analyzes a viewer’s troubled oak trees and textures up drought gardens with standout clumping grasses. John demonstrates how to plant cold-hardy succulents in hanging baskets.


Question of the Week

What’s wrong with my young live oak trees?

Jennifer Valdes is concerned about one of her two young live oak trees, both planted by the builder a couple of years ago, just before she and her family moved into their new home.

In spring 2017, they noticed that one tree is very bare at the top, and that many of the leaves on this tree have brown spots on them. The other tree is showing neither of these symptoms.

Jennifer says that both trees are getting plenty of sun, the root zones are well-mulched to the dripline (but not touching the trunk), and they’re watered twice a week, with a dedicated bubbler.

All of that sounds really good, Jennifer, so my educated prognosis is that there were issues with the tree prior to planting, and perhaps that it was planted too deeply. Both are very common with newly planted trees.

Those brown spots appear to be oak leaf blister, but there doesn’t seem to be much of it, and the recommendation for that problem is to let it run its course.  High humidity for months can spur fungal diseases that give way in dryer years.

Many trees planted in new neighborhoods, with newly constructed home, are rather stressed before they ever see your landscape. It’s very easy for large lots of trees to become pot-bound, since they are grown to a certain size, then not transplanted again. So they stay too long in a too-small container, while waiting to be taken to a new landscape, where they will then get the love and attention that they need. Circling roots develop, leading to sections of the tree being cut off from its lifeline to the roots that support its growth, leading to selective die-back.

You’re doing all the right things—including watering deeply—so see what happens in the next year. If the troubles continue, consider consulting a certified arborist.

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Plant of the Week

Clumping Grasses

Clumping Grasses

Clumping or bunchgrasses, often called ornamental grasses, are a group of plants that we love, and not a single species, or even genus. Clumping grasses come in many sizes and colors, making them a unique and stunning textural garden standout. Since deer don’t prefer them, they companion well with deer-resistant succulents and perennials. Ornamental grasses like native Lindheimer and Gulf muhly, and the various pennisetums like purple fountain grass, all have the same clumping habit and require similar maintenance and growing conditions. They vary greatly in size, so check the plant tag for mature size. Some, like Lindheimer muhly, need lots of room to allow for its at least 3-4 feet height and width. Some pennisetums are tiny and easily tucked into small gardens. Others, like purple fountain grass, get quite large. Native grasses like muhly are perennial, but others—like the pennisetums—may well be annual, depending on winter temperatures and your microclimate. They have a shallow root system, so they tolerate various soil types, but their growing areas are at the base, very close to the soil surface, so care needs to be taken that they don’t stay too wet, or they’ll rot. Most want full sun. For filtered shade under trees, choose soft-leaved Mexican feather grass (Nassella tenuissima). Mexican feather grass easily seeds into preferred areas of good drainage. Clumping grasses will need to be divided every few years, and need to be sheared to a “flat-top” yearly, depending on each one’s size, back to 6 inches or so from the ground. Shear in late winter, just before new spring growth is set to emerge. That will happen once temperatures begin to warm, so the timing may be earlier or later each year. They provide swaying, colorful interest in the winter. In late spring through winter, many have colorful seed heads that are soft and fuzzy and reflect the sunlight rather uniquely. Many provide habitat for overwintering butterflies or nesting sites for birds.