University of Minnesota Extension
Is your grandmother’s pass along Christmas cactus blooming really early? Do the leaf segments have “teeth” along the edges? Are the “stringy things” sticking out of the flowers yellow in color? Well, I hate to tell you this, but that is not a Christmas cactus, (Schlumbergera bridgesii). It is a Thanksgiving cactus, (Schlumbergera truncata). You can tell the Thanksgiving cactus apart from the Christmas cactus by the shape of the leaves and flower anthers. The leaves, botanically referred to as phylloclades, are serrated on the Thanksgiving cactus. Additionally, the pollen-bearing anthers in Thanksgiving cactus flowers are yellow. Christmas cactus have smooth-edged leaves and pinkish-purple anthers. Both of these species are native to the coastal mountains of south-eastern Brazil, where they are found growing in trees or on rocks. Therefore, the preferred potting media for Thanksgiving and Christmas cacti should contain about 40% perlite to ensure good drainage and aeration. To care for your Thanksgiving cactus, allow the soil to dry out when it is not blooming. As flower buds develop, the soil should be moist to the touch. However, overwatering can kill the plant. Additionally, provide plenty of indirect light and temperatures of 60-65 degrees F. Want to get last year’s plant to bloom again? Beginning in mid-September, it will need 12-14 hours of total darkness along with cool (60-65 degrees F) nighttime temperatures for 3-4 weeks. To achieve the light control the cactus can be placed in a closet or covered with a large brown paper bag overnight. Once buds start to form, fertilizer can be applied to encourage growth and blooms. However, flower buds will fall off with any significant changes in temperature (below 50 degrees F), light or watering.
Now, if your “Christmas cactus” doesn’t set flowers until spring, it is probably an Easter cactus, a totally different species (Rhipsalidopsis gaetner). The leaf margins of Easter cactus have small bristles and are more three-dimensional with a thick ridge on one side. Additionally, the flower are more star-shaped than the other two cacti. All three cacti species have flowers that come in a range of colors including variations of red, pink, peach, purple, orange or white.
Looking to add something to brighten your landscape this autumn? Firespike (Odontonema strictum) is a prolific fall bloomer with red tubular flowers that are very popular with hummingbirds and butterflies. It’s glossy dark green leaves make an attractive large plant that will grow quite well in dense shade to partial sunlight. In frost-free areas firespike grows as an evergreen semi-woody shrub, spreads by underground sprouts and enlarging to form a thicket. In zones 8 and 9 it usually dies back to the ground in winter and resprouts in spring, producing strikingly beautiful 9-12 inch panicles of crimson flowers beginning at the end of summer and lasting into the winter each year. Firespike is native to open, semi-forested areas of Central America. It has escaped cultivation and become established in disturbed hammocks throughout peninsular Florida, but hasn’t presented an invasive problem. Here in the Panhandle, firespike will remain a tender perennial for most locations. It can be grown on a wide range of moderately fertile, sandy soils and is quite drought tolerant. Firespike may be best utilized in the landscape in a mass planting. Plants can be spaced about 2 feet apart to fill in the area quickly. It is one of only a few flowering plants that give good, red color in a partially shaded site. The lovely flowers make firespike an excellent candidate for the cutting garden and is a “must-have” for southern butterfly and hummingbird gardens. Additional plants can be propagated from firespike by division or cuttings. However, white-tailed deer love firespike too, and will eat the leaves, so be prepared to fence it off from “Bambi”.
Each fall, nature puts on a brilliant show of color throughout the United States. As the temperatures drop, autumn encourages the “leaf peepers” to hit the road in search of the red-, yellow- and orange-colored leaves of the northern deciduous trees. In Northwest Florida the color of autumn isn’t just from trees. The reds, purples, yellow and white blooms and berries that appear on
Monarch butterfly on dense blazing star (Liatris spicata var. spicata).
Beverly Turner, Jackson Minnesota, Bugwood.org
many native plants add spectacular color to the landscape. American Beautyberry, Callicarpa americana, is loaded with royal-colored fruit that will persist all winter long. Whispy pinkish-cream colored seedheads look like mist atop Purple Lovegrass, Eragrostis spectabilis and Muhlygrass, Muhlenbergia capillaris. The Monarchs and other butterfly species flock to the creamy white “fluff” that covers Saltbrush, Baccharis halimifolia. But, yellow is by far the dominant fall flower color. With all the Goldenrod, Solidago spp., Narrowleaf Sunflower, Helianthus angustifolius and Tickseed, Coreopsis spp., the roadsides are golden. When driving the roads it’s nearly impossible to not see the bright yellows in the ditches and along the wood’s edge. Golden Asters (Chrysopsis spp.), Tickseeds (Coreopsis spp.), Silkgrasses (Pityopsis spp.), Sunflowers (Helianthus spp.) and Goldenrods (Solidago spp.) are displaying their petals of gold at every turn. These wildflowers are all members of the Aster family, one of the largest plant families in the world. For most, envisioning an Aster means a flower that looks like a daisy. While many are daisy-like in structure, others lack the petals and appear more like cascading sprays. So if you are one of the many “hitting the road in search of fall color”, head to open areas. For wildflowers, that means rural locations with limited homes and businesses. Forested areas and non-grazed pastures typically have showy displays, especially when a spring burn was performed earlier in the year. Peeking out from the woods edge are the small red trumpet-shaped blooms of Red Basil, Calamintha coccinea and tall purple spikes of Gayfeather, Liatris spp.
Visit the Florida Wildflower Foundation website, www.flawildflowers.org/bloom.php, to see both what’s in bloom and the locations of the state’s prime viewing areas. These are all native wildflowers that can be obtained through seed companies. Many are also available as potted plants at the local nurseries. Read the name carefully though. There are cultivated varieties that may appear or perform differently than those that naturally occur in Northwest Florida. For more information on Common Native Wildflowers of North Florida go to http://edis.ifas.ufl.edu/ep061
Chaste tree. The showy chaste tree makes an attractive specimen as the centerpiece of your landscape bed or in a large container on the deck. Easy-to-grow, drought resistant, and attractive to butterflies and bees, Vitex agnus-castus is a multi-stemmed small tree with fragrant, upwardly pointing lavender blooms and gray-green foliage. The chaste tree’s palmately divided leaves resemble those of the marijuana (Cannabis sativa) plant; its flowers can be mistaken for butterfly bush (Buddleia sp.); and the dry, darkened drupes can be used for seasoning, similar to black pepper, making it a conversation piece for those unfamiliar with the tree.
Vitex , with its sage-scented leaves that were once believed to have a sedative effect, has the common name “Chastetree” since Athenian women used the leaves in their beds to keep themselves chaste during the feasts of Ceres, a Roman festival held on April 12. In modern times, the tree is more often planted where beekeepers visit in order to promote excellent honey production or simply included in the landscape for the enjoyment of its showy, summer display of violet panicles.
Chaste tree is native to woodlands and dry areas of southern Europe and western Asia. It will thrive in almost any soil that has good drainage, prefers full sun or light shade, and can even tolerate moderate salt air. Vitex is a sprawling plant that grows 10-20 feet high and wide, that looks best unpruned. If pruning is desired to control the size, it should be done in the winter, since it is a deciduous tree and the blooms form on new wood. The chaste tree can take care of itself, but can be pushed to faster growth with light applications of fertilizer in spring and early summer and by mulching around the plant. There are no pests of major concern associated with this species, but, root rot can cause decline in soils that are kept too moist.
Although it has been very hot this summer throughout the Florida Panhandle, many areas have been blessed with afternoon showers several day in a row. Historically, this has been the typical Northwest Florida weather pattern known as the ‘Dog Days’.
Yet, many landscape sprinkler systems were still running. One has to ask, “Where are all the rain shut-off devices?”. Florida is one of just a few states with a rain sensor statute. Since May 1991, new installations of irrigation systems have been required to include a rain shut-off device. However, no wording was included to cover installation or maintenance. The 2010 statute change now states the following: “Any person who operates an automatic landscape system shall properly install, maintain and operate technology that inhibits or interrupts operation of the system during periods of sufficient moisture.” (Florida Statute 373.62).
Thus, ALL automatic landscape irrigation systems require rain sensors, or other shut-off devices such as soil moisture sensor irrigation controllers. No “grandfather clause” was included for existing systems. Regardless of when it was installed, every sprinkler system must have an operational rain shut-off device. Irrigation contractors can be fined for working on a system without checking out and/or connecting a device.
Moisture sensing technology conserves water, saves money, reduces wear on irrigation system components, reduces disease and helps protect water resources from runoff. Previous research has shown that homeowners using in-ground, automatic irrigation systems, typically in Florida, apply 47% more water for landscape irrigation than homeowners without automatic irrigation systems. This over-irrigation is largely due to a “set it and forget it” mentality despite seasonal fluctuations in plant water needs. If the water costs and the amount of water applied per watering cycle are known, it is easy to calculate how much money is being saved each time the sensor interrupts the program. For example, if a system irrigates ½ acre of turf and is set to deliver ½ inch of water to each zone, approximately 13,576 gallons of water will be used during each watering event. If the cost of the water is $2.00 per thousand gallons, every time the sprinkler system comes on the water bill will be $27.15. A significant amount of money and water can be saved by maintaining a rain shut-off device.
Irrigation is common in Florida landscapes because of sporadic rainfall and the low water holding capacity of sandy soils. Water conservation is a growing issue due to increased demands from a growing population. The least expensive and most common rain sensor device is the expansion disk rain shut-off. Expanding cork disks trigger a pressure switch. The expansion space can be easily adjusted by rotation of the disk cover to a predetermined amount of rain required to trigger the switch. The amount of rain that will interrupt the irrigation system is marked on the adjustment cap. A rain sensor must be mounted where it will be exposed to unobstructed rainfall, typically installed near the roofline on the side of a building.
Irrigation control technology that improves water application efficiency is now available. Soil moisture sensors (SMS) can reduce the number of unnecessary irrigation events. Most soil moisture sensors are designed to estimate soil volumetric water content based on the soil’s ability to transmit electricity, which increases as the water content of the soil increases. Bypass type soil moisture irrigation controllers use water content information from the sensor to either allow or bypass scheduled irrigation cycles on the irrigation timer. Another type of control technique with SMS devices is “on-demand” where the controller initiates irrigation at a low threshold and terminates irrigation at a high threshold. A single sensor can be used to control the irrigation for many zones or multiple sensors can be used to irrigate individual zones. In the case of one sensor for several zones, the zone that is normally the driest, or most in need of irrigation, is selected for placement of the sensor in order to ensure adequate irrigation in all zones. Sensors should be buried in the root zone of the plants to be irrigated. For turfgrass, the sensor should typically be buried at about three inches deep. The placement of SMS should be at least 5 feet from hard surfaces and sprinkler heads. The sensor needs to be calibrated and/or the soil water content threshold needs to be selected.
The amount of water that can be saved using rain shut-off devices is substantial since water use increases substantially during summer months. Remember that every drop that hits the ground will be picking up pollutants as it flows to our groundwater. Nonpoint source pollution is the leading cause of water quality problems. These pollutants have harmful effects on drinking water supplies, recreation, fisheries and wildlife. By only irrigating when the soil needs it, you are also preventing contamination of drinking water.
This article is being reissued as part of our ‘Best Of” series, from August 2013 .