Diana C. Kirby, Author at Diana's Designs Austin

About Diana C. Kirby

Diana Kirby is a lifelong gardener and longtime Austinite, who loves the Central Texas climate for the almost year-round opportunities it offers for active gardening and seasonal splendor. Known as an impassioned and successful gardener, Diana began by helping friends design and implement their landscapes. Soon, she was contracted as a professional designer by a popular local landscaping installation firm, where she designed landscapes for residential and commercial clients for several years. In 2007, her new passion blossomed with the launch of her own firm, Diana’s Designs. ... Diana is a member of the Association of Professional Landscape Designers, the Garden Writers Association of America, and she writes a monthly gardening column for the Austin American-Statesman. Diana teaches the Landscape Design classes for several county Texas Agrilife Extension Service Master Gardener certification programs and speaks about gardening and design for garden centers and other groups. Learn more about presentation topics, availability and speaking fees.

Spring in full swing at Lady Bird Johnson Wildflower Center

It was a beautiful morning. Drizzling, foggy, chilly and damp. But, I was at the Lady Bird Johnson Wildflower Center spring plant sale with my friend, Laura, of Wills Family Acres, with a smile on my face and money in my pocket!

Modified for Covid protections, reservations were required and the sale has been stretched out over multiple weekends. While there were less plants in a smaller space, that wasn’t surprising given the winter we just had and the spreading out of the event time.

As is often the case in the spring, we were greeted by one of the baby owlets that are hatched each year. For the last 10+ years, the entrance to the center has been home to a pair of great horned owls. The mom’s name is Athena, and she and her little ones can be seen high above the entrance arch for 6 to 7 weeks in spring. Can you see the little one peeking over the ledge just under plant on the right side? Learn more about our iconic feathered friends here

They still had lots of great natives in 4-inch pots and gallons. Sun plants, shade plants, trees, agaves and grasses and yuccas. As always, I was fascinated to learn about natives new to me, and a few of them ended up in my cart. (Surprise, surprise!)

I’m trying Geum canadense, a woodland herb that grows as a ground cover in a woodland setting, it has strawberry-like evergreen foliage and a sweet little white bloom April – June. Also new to my garden, I bought a Solidago – I admire them every fall and have said for years that I’d like to have one. Well, now I do!

I also picked up several of my annual sale favorites – Helianthus maximus, calylophus, Henry Duelberg salvia, and Datura. Having a new garden helps me rationalize my purchases these days.

After our retail therapy, we treated ourselves to a leisurely walk around the grounds. The spring wildflowers and other bloomers blanket the beds, filling them with a patchwork of colors and textures like a beautiful quilt.

Engleman’s sage clusters brightened the beds all through the grounds.

Winecup makes a beautiful border.

Several windows create a secret garden effect, allowing visitors to peek from one part of the garden into another.

I’ll try to keep up my blogging momentum and post the rest of my pics this week, so pop back over!

By Diana C. Kirby|2021-04-19T11:09:05-05:00April 19th, 2021|Engelman's daisy, geum, hardscape, Lady Bird Johnson Wildflower Center, Sharing Nature's Garden, spring, spring bloomers, spring planting, winecup|5 Comments

Diana Explains Dead or Dormant in Interview by The Best of JB & Crew On Austin 360 Radio

Now that the crisis is over..we are looking at our landscaping and wondering how to save the plants! JB and Whitney talk with landscape designer Diana Kirby of Diana’s Designs. She gives us the critical tips to help us figure out how to save our plants!

By Diana C. Kirby|2021-02-26T09:36:47-06:00February 26th, 2021|Austin 360 Radio, dead, dormant, The Best of JB & Crew|2 Comments

Dead or dormant? How to tell if your plants survived Texas’ winter blast

Last week Central Texans watched as snow and ice blanketed landscapes in a series of storms rivaling Northern blizzards.

As power is restored, water becomes safe to drink and the process of repairing damage has begun, it’s time for garden assessment.

It’s ugly out there. Finally able to walk my dogs, I found downed tree limbs or cut brush at almost every house in our neighborhood. Prized agaves, sago palms and other specimen plants turned to rotting mush. Tough-as-nails rosemary bushes sport black branches. This unprecedented freeze damage has left even seasoned gardeners wondering what will return and what’s gone for good? Is it dead or is it dormant?

We normally only have a few weeks left until the danger of frost has passed. According to the USDA Hardiness Zone map for the Austin area, our average last frost occurs between March 1 and March 31. It’s usually the middle of March. But it hasn’t been a typical winter.

Cacti that are mushy and seeping probably won’t make it to summer after the winter snow and ice.

The most important thing right now is to wait. If you prune a dormant plant right now and warm weather stimulates growth, the new leaves will be highly susceptible if we have another freeze, and it will then die. If you wait until the danger of frost has passed, you will give your dormant plants a fighting chance.

The center of this sago palm should be checked. If it is still hard, it should make it.

Palm trees

Native Sabal minor palm trees tolerate freezes in most years. Most other palms won’t make it. If the center bud is firm, the plant might survive. Cut off drooping, dead or damaged leaves. If your palm has a rotting crown, or you can easily pull fronds out of the trunk, it won’t come back. If you’re unsure, however, give it plenty of time to recuperate.

Cycads – Sago palms

Many Austin gardeners enjoy the drama of large Sago palms in their landscapes. Not actually palms, Sagos are cycads. They generally tolerate temperatures down to 15 degrees. Frost-damaged leaves turn yellow or brown and should be removed. If the trunk and leaf crown are hard wood, it should recover. If the trunk turns soft, your sago might be damaged beyond recovery. After the freeze of 2010, Sagos across town were devastated but most had no crown damage. By summer, new leaves emerged and the plants thrived.

This rosemary has survived 20-plus years, but not the winter storm of 2021. It probably won’t come back.

Shrubs and woody perennials

Rosemary normally does fine in our mild winters, even handling a few light frosts for short periods. Days on end of single-digit weather and wet snow spelled the end of the road for even the most established plants. You can remove them at any time — they won’t be coming back.

Salvias range from cold hardy to tender. Some Salvia Greggiis even survive to 0 degrees. If you don’t know your exact variety, the best approach is to cut them back to green wood. Once you see green inside the cut, stop. If you don’t see any green, simply cut it back to the ground and be very patient. It may come back from the roots, given a few months.

Salvia can be cut down to see if there is green in the branches.

Take the same approach with shrubs and other woody perennials that appear dead like pittosporum, loropetalum, lantana and boxwood.

Succulents

We know some plants simply aren’t cold hardy. Many agaves, cacti and other succulents won’t survive after the prolonged deep freeze and snow. A handful of species might have weathered the storm, and you’ll know if there is hope if you have a firm center inside the collapsed outer leaves.

Sotols, Yuccas and Nolinas are usually Texas tough. Many in my garden and elsewhere are looking great after the winter assault. Whale’s tongue and havardiana agaves are reported to have survived in some landscapes as well.

The plants might look bad right now, but some of them might surprise us by summer.

Cacti

Crumbled mounds of mush, prickly pear cacti simply disintegrated all over town. There might be hope for some of them, however, depending on the species. Some varieties of Optunia are hardy to 15, 10 or 0 degrees.

Agave might look very bad right now, but some of them might survive.

Cacti are very sensitive to the timing of pruning. While their dying pads and stems look terrible, it is important to wait until it is really warm to prune them. Then dust the big cuts with sulfur to help dry out the cuts. Jointed cacti regenerate really well, but the columnar ones should be cut back to the base or you will just end up with a permanent stump. If the plant is oozing, you can remove it now.

Our plants took an incredible hit. Those that survive will need much longer to recover than milder years.

Once, after a terrible freeze, I advised my clients repeatedly to wait longer before pulling out plants. I ignored my own advice and ripped out a very small Anacacho Orchid Tree only to find the tiniest green growth at the base of the plant that was hidden by mulch. So, wait, wait, and wait some more.

By Diana C. Kirby|2021-02-26T09:36:05-06:00February 26th, 2021|Articles, Austin American Statesman, cacti, cactus, dead, dormant, palms, perennial, Sago, shrubs, succulents, woody perennial|0 Comments

Heat Stress Solutions for Landscape Plants

During the dog days, when rain is scarce and scorching is the order of the day, many plants will wilt and burn. The summer sun brings blooms, but as temperatures climb to triple digits, it takes a toll on our gardens.

We can’t turn down the outside thermostat, but there are things you can do to help your garden weather the heat.

When it’s sweltering outside, our bodies sweat to cool off. Plants sweat to cool off too, through a process called transpiration. Transpiration is basically water movement through the plant and the resulting evaporation from the leaves, flowers and stems. The plant takes water and minerals from the roots and sends it to the leaves. In extreme heat, this loss of water can be devastating. If the water loss isn’t made up by more replacement water in the soil, the plant will wilt and begin to decline.

Water right

How you water makes as much difference as how much you water. Because most sprinklers lose a lot of water to evaporation, watering should be done in the predawn or early morning hours to prevent scorch and maximize the amount of water going directly to the plants. Don’t be tempted to water more often. Frequent light watering actually hurts plants, encouraging them to keep shallow roots. Longer, less frequent watering develops deep roots — away from the hot soil surface – that require less water.

Drip irrigation provides the most efficient way to water. Keeping water next to the plants and using minimal pressure, there is almost no evaporation or runoff with drip irrigation. Because this method releases water so slowly, watering takes much longer, so make sure your plants are getting enough. Ensure the hose is properly positioned – it should reach around the plant roots.

Of course, using rainwater is great when you can get it. Plants always prefer natural rainwater to chemically treated tap water. Whether you use rain barrels or buckets or a cistern, collect as much as you can.

And sometimes, even more water isn’t enough. When we hit triple digits, hot is just plain hot. In the scorching sun, plants can get sunburned just like we do. Plant sunburn generally appears in the middle of the leaf because edges and leaf tips can dissipate heat better. If your plants are burning, try to provide some temporary shade until temperatures come back down a little.

Mulch well

Any bare ground that is not mulched radiates heat directly onto your plants. A good layer of wood much insulates the soil, reducing water loss from the soil surface and protecting plants against heat. Mulch helps prevent evaporation and retains water to keep plant roots moist. And, it also helps control weeds that also compete for any available water.

Don’t Fertilize

As you begin to see signs of stress in your plants, fertilizing them might seem like the thing to do. Don’t. Fertilizing them will push them to grow, adding even more stress. The best plan is to feed them before the stress of summer, so they are better able to handle the heat when it soars.

Identify pests and disease

Keep an eye out for pest damage and plant disease at this time of year. Plants already struggling with health issues will quickly succumb to heat and drought. Check for detrimental insects often. Look under leaves and inspect in the evening, when many pests are more active. Be careful not to use chemical products that will hurt the beneficial insects in your garden that control pests naturally.

Other causes of stress in plants can be exacerbated by the heat. In my garden, late summer marks the onset of chlorosis in some plants. Common in clay and limestone soils high in pH, this nutrient deficiency keeps plants from synthesizing the chlorophyll they need, causing leaf yellowing. There are many causes of yellowing, including over and under watering. Consult with your independent garden center if you’re unsure about the cause.

Top Tips to Handle the Heat