I get a lot of questions asking for “a beautiful shrub that has few or no pest problems, that will grow in sun or shade and in a wide variety of soils, “Oh, and I want it to bloom. A lot.”
That’s when I ask, very much under my breath, “Any other restrictions you’d like to throw on the pile?” I know that I’m going to have my work cut out for me coming up with an answer that will come anywhere near pleasing them.
Here are the challenges. First, almost all flowering shrubs only bloom one time per year, usually for a couple of weeks. No matter how many times you subtract two weeks from a whole year, you’re left with 50 weeks that may or may not be beautiful. That’s huge!
Second, most flowering shrubs are deciduous. They’re bare over the winter. That’s for four or five months, and that’s almost as big. Unless the plant has some kind of redeeming trunk and bark character, that’s four or five months of “bland.”
Undeterred, though, I’ve decided to construct a list of our common North Texas flowering shrubs — and then to arrange them in my estimation of their landscaping contributions. In more than 40 years of writing, this is the first time I’ve ever attempted this. It’s going to be absolutely subjective — one guy’s opinion, but I’ll try to explain my reasons along the way. Remember, these are not listed in sequence of bloom, but in order of how I would rate them as landscaping contributors.
1. Crape myrtle. Many mature sizes and colors. Full sun. Easily trained tree-form. Attractive trunks in winter. Aphid and scale insects do little damage and are fairly easily controlled. Blooms several times during summer if people can resist the senseless urge to butcher (“top”) their plants.
2. Abelia. Large, arching evergreen shrub to 6 or 8 feet tall and wide. Small, white flowers are produced all summer long. Dwarf and variegated types are in the market. Best in sun. Tolerates some shade.
3. Althaea (rose-of-Sharon). Large deciduous shrubs to 8 to 18 feet tall and wide. Single or double flowers in shades of rose, pink, lavender, white and bicolors from late spring through summer. Cotton root rot is a problem.
3. Bridal wreath (Spiraea). Arching deciduous shrub to 4 to 5 feet tall and wide. Covers itself with small white blooms in spring. Not unattractive rest of year, but certainly not showy. No major problems. Sun or part sun.
4. Oakleaf hydrangea. Large woody shrub to 6 feet tall and 7 or 8 feet wide. Smaller selections are available. Huge, star-shaped leaves. 10-inch floral displays in late spring. Shade, moist soils. Can show iron deficiency. Handsome and durable shrub.
5. Forsythia. Grows to 7 feet tall and wide. Covers itself with buttery yellow blooms in early spring — an unusual color for flowering shrubs. Slightly above average appearance during growing season and bare in winter. No major problems.
6. Italian jasmine. Difficult to find, this arching shrub grows to 5 feet tall and 6 feet wide. It’s leaves are deepest green and evergreen. Its small white flowers start appearing in late winter and persist through the spring. Sun or shade. No pest problems. Should be more common.
7. Snowball viburnum. There are several viburnums producing large, rounded white flower clusters. They grow best in shade and with consistently moist soils. Deciduous, with no common pest problems. (Spring Bouquet, another species of viburnum, is not winter-hardy in our area.)
8. Mock orange (Philadelphus). Rarely seen in local gardens, it could be more widely used. Grows to 8 to 10 feet tall and wide. It produces fluttery white blossoms in the spring. Best in moist soil and shaded conditions.
9. Azalea. Premier evergreen flowering shrubs, but must have acidic planting soil. That means replacing Blackland clay soil entirely with 18 inches of sphagnum peat moss/finely ground pine bark mulch in equal amounts. If it weren’t for that requirement, azaleas would be among the very top-rated flowering shrubs. Morning sun, afternoon shade.
10. Texas mountain laurel. Full sun, perfect drainage are requirements. Beautiful evergreen with highly fragrant lavender flower clusters that hang like grapes. Grows to 10 to 14 feet tall and 10 feet wide. Somewhat winter-tender in North Texas or I would score it much higher.
11. Anthony Waterer spiraea. Blooms one month after bridal wreath. Magenta flowers on deciduous stems. Grows to 3 feet tall and wide. Tends toward iron deficiency due to alkaline soils, water. Otherwise it would rank higher. No pest problems.
12. Pomegranate. Both edible and ornamental types are seen. Ornamental types have fully double flowers in late spring. Their fruit is colorful but not edible. Edible varieties are still very attractive — flowers just aren’t as showy. Deciduous. Slightly winter-tender in North Texas. Full sun.
That takes us to a natural dividing line. There are other flowering shrubs that are a step down in appearance or dependability. They include, still in my arbitrary order of descending quality: gardenias (very risky in cold winters and prone to insect and disease problems); oleanders (extremely winter-tender); flowering quince (gorgeous while blooming, but ugly when not); Texas sage (intolerant of cold and poor drainage, pest problems, over-used); Indian hawthorn (highly susceptible to fatal Entomosporium fungal leaf spot); and mophead hydrangeas (those the florists sell — iron deficiency, winter-tender, difficult to maintain and poor performers in our area).