Fire ants and other insects in the compost pile
If you’re an active composter, you’ll definitely have insect larvae in your pile, and that’s a good thing. These creatures are helping the microbes to break down the food waste in your pile and turn it into rich compost. Large, off-white grubs are very commonly found in compost piles, and people often mistake them for the same grub that damages our lawns. But the grubs in your pile are from a different species of insect, not the June beetle larvae that eat the roots of your turfgrass and other plants. You might also find black soldier fly larvae in your compost pile, which are also good. The insect species that are attracted to lay eggs in your pile will be influenced by what you put in it. If you have more kitchen scraps and food waste, you’ll likely have more insect larvae. If you’re only composting yard waste, you may not see as many creepy crawlies. But fire ants are another matter. Fire ants are actually building their mounds in the nice, soft organic matter of your compost pile. Although they’re doing some aeration and technically aren’t hurting anything in the pile, you most likely still don’t want them living there, since they’ll see the pile as theirs, not yours. If you have a mound of fire ants in your pile, it indicates that you need to turn and moisten the pile more often. If you’re regularly turning the pile, the ants will have no time to build a home. During a hot summer, I didn’t turn my pile as much as I should have and I came out one day to discover that a very large colony of fire ants had moved in. I got stung a few times when turning it and it took a few turns to get the ants to move away, but they eventually did. So there’s no need to use any chemical fire ant treatments in this situation.
Tomatoes with mushy black or brown rot on the bottom ?
This is blossom end rot. Thanks to viewer Russell for sending a picture. Blossom end rot is a common disorder in tomatoes, but may also be found in peppers and eggplant. It’s caused by a calcium deficiency in the fruit, but adding calcium to the soil won’t solve the problem. As plant cells are developing, they require a lot of calcium. And tomato fruit develops quite rapidly, sometimes depleting the plant’s available calcium supply. There are many reasons why your tomato fruit may develop faster than it can replenish its calcium, but usually the reason is irregular watering. Soil that is very wet, when you irrigate, then very dry, between waterings, leads to irregular water-uptake and fruit that develops in fits and starts. Usually blossom-end rot is only a problem for the first harvest of the season, then plant growth kind of evens out, and water-use by the plant evens out a bit too. When growth and water uptake occur at a steady rate, the fruit develops in a more even manner as well and cells in the fruit receive enough calcium to develop properly. Certain cultivars and varieties of tomatoes are more prone to blossom-end rot, so you may want to choose different varieties next year, if you have a large problem with a particular variety this year. If you continue to have issues, you might try using sulfur to acidify the soil a bit and using a fertilizer with nitrogen in the nitrate form, not the ammoniacal form. Calcium sprays to the plant don’t remedy the situation much, since not much of the calcium applied to the leaves gets into the fruit, where it’s needed.
All about ferns
Viewer Heidi noticed one day that the bottoms of the leaves on her ferns were covered in strange black spots. We were happily able to soothe Heidi’s frayed nerves, since these are nothing to worry about at all. The splotches are actually very natural, and indicate a very happy plant indeed. Ferns are ancient plants that still reproduce from spores, rather than going to all the trouble of producing flowers to attract those pesky, unreliable pollinators. Ferns are native to areas with high relative humidity, which is important in their reproductive cycle. Here in Central Texas, we have a beautiful little native fern, which can easily be seen while hiking along our many creeks and green belts. I first discovered the southern maidenhair fern, Adiantum capillus-veneris, while out on hikes with my plant systematics 101 class here at UT Austin. Dr. Billie Turner would be proud that I remembered that tongue-tier of a species name! Okay, back to Heidi’s fern. Is there anything special she should do with it now that it’s producing spores? No, not really. You might notice a bit of a mess as the spores dry up and fall off, but the plant will happily go about its own life, whether any offspring result or not. Just keep on doing whatever you’re doing Heidi; you’re fern sounds like it’s very happy in your care.
Why do cucumber and squash flowers fall off the plant before fruit is produced?
I love this question, since it involves so much of the easy science behind the life cycles of flowering plants. Some plants have very little trouble with pollination, while others struggle. Plants in the Cucurbitacea, the squash family, can have a challenging time with pollination, especially with our native bee population in decline. As you know, squash, cucumbers, and other pepos, as they are often called by vegetable gardeners, have a long, full fruit with lots of seeds. Well, in order for that fruit to develop at all, and then to expand and elongate, pollination must occur. If there’s no pollination, the plant has no reason to make a fruit. A fruit without offspring would be a serious waste of resources, and Cucurbits simply don’t waste their time. If a little bit of pollination occurs, then a few seeds will develop and the fruit will expand, but will be very small. It’s all part of nature and the conservation of precious resources for survival. Unfortunately, lack of pollination in squash and cucumbers is very common, but the good news is, the problem is easily solved: you can pollinate the flowers yourself. Many gardeners tell me that they simply use their forefinger to grab a little pollen from one flower and use it to pollinate the next. Fancier folks might use a paint brush to do the same job, especially if they’re doing controlled cross-hybridization between species and want to ensure against contamination. You can also simply remove one flower and use it to pollinate the others. Plants in the squash family have two types of flowers: male and female. The female flowers produce the fruit, which you can see as a tiny swollen area behind the tubular flower. Male flowers contain the pollen, so be sure to remove a male flower to use as your pollen source, then simply press the pollen down into the center of the female flower, onto the stigma, which is the elongated part of the flower, in the center. Make sure that you get plenty of pollen on that stigma. All of the seeds in the flower need to be pollinated, or the fruit will be small and underdeveloped.
There are two very common species of Caesalpinia in the nursery trade: pulcherrima and gillesii, and both are quite beautiful. Caesalpinia pulcherrima is most commonly known as Pride of Barbados or red bird of paradise. It has orange-yellow flowers and is a little bushier than Caesalpinia gillesii, which is most commonly known as yellow bird of paradise, because it has all yellow flowers. Both plants love the heat, need full sun, and prefer very well-drained soil. These plants will bloom all summer long with very little supplemental irrigation, so be careful not to overwater them. Both plants may freeze to the ground in winter, but not always. If you notice leaves reemerging on the plant in the spring, the plant was not damaged by the cold and may be left alone. But as temperatures warm up, if you notice growth at the base of the plant, from the roots, and not from the branches, go ahead and prune off all the top growth and allow the plant to reemerge from the roots. Pride of Barbados, the orange flowered one, is more frost tender, and does freeze to the ground in our winters more often than not. Both plants can get up to about 8 feet tall, but Pride of Barbados is generally a little shorter and bushier, mostly due to the fact that it freezes to the ground most years. And both plants get about 4 to 6 feet wide, so give them plenty of room. Both plants attract hummingbirds and butterflies and are considered to be deer resistant.
There are many different species in the genus Manfreda. You may also find hybrid Agave/Manfreda crosses, called Mangaves. All are native to the southern US, Mexico and Central America and are great succulents for your garden. One species of Manfreda is known as Texas tuberose. As with most succulents, Manfredas require loose, airy soil with excellent drainage. Gardener Brent Henry has clay soil so he mixes in decomposed granite to improve drainage. His Manfredas get partial sun with most of the sun in the afternoon, but shaded by a bur oak. He gives them practically no water, and all have survived hard freezes and tough droughts just fine. They bloom reliably every spring with a 4 foot spike. Manfredas have a low-growing, rosette habit and don’t take up much space in the garden. With their long, sometimes curly leaves, they also look great in containers, especially when the container color plays off the spots on the leaves.
Brazilian rock rose, Pavonia hastate, also known as pink Pavonia
Like our native rock rose, this species is a relative of the more tropical Hibiscus, but with more drought and cold tolerance. Plant Brazilian rock rose in full sun and give it plenty of space, since it can get up to 3 feet tall and 4 feet wide. In a bit of shade it will stay smaller, but will still flower prolifically. The petals of pink Pavonia flowers are pale-pink, almost white, with a deep magenta center, attracting a crowd of butterflies and hummingbirds to your garden all summer long. As its name implies, rock rose will do just fine in rocky soils, making it a great choice for rocky Hill Country gardens, and also in xeriscaped areas of the garden with decomposed granite or other gravelly substrate. In mild winters, Brazilian rock rose may be evergreen, but will be deciduous in colder winters. There’s no need to shear to the ground in winter, but a light pruning in very early spring will encourage bushier, less leggy growth. If you have the time, lightly shearing during the growing season will also encourage more of those gorgeous little flowers. Plant Brazilian rock rose along walkways and paths, where it will have space to spread out gracefully, and soften surrounding hardscapes.
Duranta, also known as Brazilian sky flower
This rapidly growing shrub can get 10 to 15 feet tall and over 5 feet wide. It’s listed as hardy to only zone 9, so here in Central Texas, it dies to the ground in winter in most gardens. But in our demonstration garden at the Extension office, Duranta is evergreen, hardly even skipping a bit in the coldest of winters. We have it planted against a wall, with full sun exposure all day, so the heat that builds up during the day is radiated during the night, keeping the microclimate much warmer there than in other areas of the garden. If Duranta dies to the ground in winter in your garden, simply prune it back to about 3 inches from the ground and it will reemerge from the roots in spring. There are several cultivars of Duranta, but my favorite is the purple-flowering one. It flowers from early spring all the way through fall and doesn’t bat an eyelash at heat or the lack of rainfall. We also have a white flowering cultivar in our garden, and it’s also very pretty, and forms more pretty yellow, ball-like fruits than other cultivars. If you want to attract native birds to your landscape, they’ll love the fruit of the white-flowering cultivar. Duranta will perform best in full sun, but can take light shade.