Summer Annuals Are Grateful For Deadheading

Blooming through summer is serious work.

So many of the pretty warm season annuals planted last spring are now at their best. Sweet alyssum, lobelia, verbena, moss rose and busy Lizzy never stop blooming, and only get more colorful as they grow through the season until they get replaced by cool season annuals in autumn. (It is unfortunate that busy Lizzy, which had been a standard warm season annual for so many years has become less available due to disease.) However, French marigold, petunia, floss flower, cosmos, statice, pincushion flower (scabbiosa) and zinnia need a bit of attention to perform as well that long.

These few warm season annuals can get tired of blooming if not ‘deadheaded’ (groomed of deteriorating flowers). Deadheading not only keeps plants looking a bit neater, but also prevents the diversion of resources needed for continued bloom into the generation of seed. As far as these blooming plants are concerned, seeding for the next generation is their priority anyway. As long as they are not allowed to set seed, they will continue to try, by producing more flowers to replace those that fade and get removed without setting seed.

Cosmos, statice and pincushion flower can continue to perform adequately without deadheading. The main advantage of deadheading these annuals is the removal of fading flowers. (There probably will not be much left for cosmos.) Many people actually prefer to leave fading cosmos flowers to disperse their seed for the following year.

Petunia is perhaps one of the more demanding of warm season annuals. It often needs to be clipped back in the middle of the season, right when it is expected to bloom the most. The best way to avoid serious pruning at one time it to keep plants snipped back lightly but continually as they grow, so that they can not develop the awkwardly long and weirdly jointed stems that eventually stop blooming. Short stems that stay close to the roots are the healthiest and most productive.

The various types of cockscomb are odd warm season annuals that become available halfway through summer, just in time to add color if some of the annuals planted earlier in spring are not performing adequately, or are finishing early. Of course, all of the other warm season annuals will still be available in nurseries until it is time for cool season annuals next autumn.

Deadhead To Promote Continued Bloom

Alyssum is too profuse for deadheading.

Deadheading is simply the removal of deteriorating bloom prior to the maturation of seed or fruiting structures. Besides diverting resources, it removes unappealingly deteriorated bloom, as well as unwanted or potentially invasive seed. Deadheading can be delayed if seed from particular flowers is desirable, (although some types are genetically variable).

It was time to deadhead spring bulbs as they finished bloom earlier last spring. Now it is time to deadhead some of the summer bulbs. It eliminates unsightly faded floral stalks of gladiolus, and diverts resources into developing bulbs. It eradicates invasive montbretia seed. For canna, it conserves resources to enhance subsequent bloom through summer. 

It is helpful to deadhead some types of annual bedding plants too. Marigold, zinnia, floss flower, pincushion flower and petunia should bloom better with systematic deadheading. Of course, all will continue to bloom without deadheading, but might be slightly subdued, with fading flowers. Modern sterile varieties that produce no viable seed are less reliant.

Fortunately, there is no need to deadhead alyssum, lobelia, nasturtium, moss rose, busy Lizzie or verbena. Their bloom is so abundant that it constantly overwhelms older bloom. Grooming tiny alyssum and lobelia flowers would otherwise be incredibly tedious. Moss rose, alyssum and nasturtium are pleased to self sow, but revert to simpler feral varieties. 

Some branched types of sunflowers produce several blooms on several separate stems. Others bloom with only a single flower on top of a tall single stem. If deadheaded prior to the maturation of their seed, the stalks of some single sunflowers generate a few smaller axillary flowers by autumn. This technique inhibits seed production, but prolongs bloom.

Houseplants Bring The Outdoors In

Many houseplants will not live outside.

There is someplace in the world for the brethren of each and every houseplant to grow wild. All houseplants do not originate from the same regions, and many were bred in cultivation, but all originate from somewhere. They are houseplants only because they are plants that can live in a house.

Most houseplants are from tropical regions, and many are understory plants that grow in the partial shade of taller trees. They are naturally tolerant of the mild temperatures and partial shade within the home. Not many deciduous plants will be happy without a winter chill.

Confinement is also a concern, since houseplants need to be potted, and stay below ceilings. Plants that need to disperse their roots will not work. Neither will plants that can not be pruned down as they grow. Some palms that work well in malls have leaves that get longer than the distance between the floor and ceiling in the home!

Most houseplants are grown for foliage instead of flowers, not only because a lack of seasons inhibits bloom, but also because their foliage is naturally so appealing. African violets are one of the more notable exceptions. Amaryllis is all flower with almost no foliage, but typically gets discarded when done blooming.

Coleus and caladiums have such colorful foliage that there is no need for flowers. Bloom actually compromises their foliar quality anyway, which is why flower spikes get snipped from coleus. Mauna loa lily is grown for excellent rich green foliage, but sometimes adds clear white blooms as a bonus.

All sorts of ferns are very good houseplants. However, a few, including the popular Australian tree fern, produce coarse fuzz that can be irritating to the skin. A few others, like sword fern, produce messy spores that can permanently stain fabric and carpet. Just because they can live in the home does not mean that they should.

The various ficus are excellent houseplants because they can grow quite large, but can also be pruned to fit into their particular situations. The popular weeping fig (Ficus benjamina) has an abundance of small glossy leaves. Rubber tree and fiddle leaf fig have big thick leaves. Creeping fig is even more distinct from the others, as a wiry vine that is popularly grown in hanging pots.

Plants To Cover New Ground

Ground cover plants are quite variable.

Lawn is both the most common and the most horticulturally incorrect of landscape features. Not many landscapes lack lawn. After all, it is the most useful part. Yet, with few exceptions, it requires more water and maintenance than anything else, and in most situations, than everything else combined!

Other groundcover plants are not nearly so greedy. Some need only occasional attentions. Most want less water, and some need very little water or none at all once established. No other groundcover functions like lawn. However, they each have particular advantages.

Ideally, groundcover plants do more than just look good. Most cover otherwise exposed soil so that weeds or other unwanted plants do not dominate. Some groundcovers help to stabilize soil. A few even work as living mulch so that soil does not stay too harshly exposed for other plants to be comfortable in it.

Low growing shrubbery, like creeping ceanothus and some types of juniper, can get too deep and unmanageable for confined areas. They tend to work better where they have room to spread outward uninterrupted. Otherwise, the edges can get quite shabby if they need to be pruned back for confinement. Some sprawling cotoneasters tolerate pruning better, both on top and the edges.

Coarse vines, like honeysuckle, naturally stay low where they have nothing to climb, although they need occasional pruning to stay tidy and confined. High branched trees, like most types of eucalyptus, are beyond the reach of busy tendrils or twining vines. However, Algerian and English ivies, although considerably tidier and uniform, can cling directly to the trunk of any tree to become a wicked mess out of reach!

Old fashioned Hottentot fig (freeway iceplant) can be aggressive where it needs to be pruned around the edges, but is actually quite complaisant otherwise. It does not pile up too deeply because older stems decay as readily as they get overwhelmed by new growth above. Vigorous growth is an advantage for filling in quickly, and subduing weeds. ‘Real’ iceplants are smaller, more docile around the edges, and much more colorful when they bloom.

Toxic Plants Are Diversely Enigmatic

Smoketree is related to poison oak.

There is no single reason for toxic plants to be as potentially dangerous as some of them are. They are toxic by various means, and to various degrees. Some actually seem to be incidentally toxic. Many are intentionally and justifiably toxic. A few live in home gardens and landscapes. Of these, a few surprisingly produce safely edible fruits and vegetables! 

Immobility is a major disadvantage for plants. Those that begin to grow where resources are inadequate are unable to relocate to more accommodating situations. Those that live within ecosystems that periodically burn must either regenerate efficiently after fire, or be resilient to fire. Flowers of all plants must rely on other organisms or wind for pollination.

Since plants are immobile, they can not evade other organisms that eat them. Therefore, some do what they can to be unappetizing for the organisms that are most threatening to them. Some use thorns or similar protective devices. Unpalatable tomentum (fuzz) works for others. Many use unappealing flavor. Some are unappetizing because they are toxic.

Toxic plants are generally not toxic to a broad range or organisms. Insects eat plants that are very toxic to mammals. Onions, although commonly consumed by humans, are toxic to canines. Fortunately, most organisms instinctively know what plants are toxic to them, and avoid eating them. Unfortunately, humans and canines are occasionally exceptions.

Because young children put random items into their mouths, and puppies chew anything that they can get their teeth around, they should not have access to toxic plants. Morning glory, foxglove, yew, oleander and castor bean are some of the more poisonous of plants that are common in home gardens. Dieffenbachia is a potentially dangerous houseplant. 

African sumac and smoketree are related to poison oak. Although not so poisonous, they are incidentally toxic allergens to those who are sensitive to them. (Incidental toxins may not be intentionally deterrent to consumptive organisms.) Hellebores are both poisonous and very allergenic. Poinsettias and their relatives are toxic because of their caustic sap. 

Humidity And Wind Affect Heat

Heat is more than mere temperature.

Gardening is not so much fun when the weather gets as warm as it has been recently. It is more comfortable to stay inside with air conditioning, or at least where it is shadier. The plants out in the garden are on their own. Except only for those that are potted, they do not have the option of coming in out of the heat.

Most plants actually do not mind the sort of heat that is uncomfortable for us. Some actually enjoy it. The problem is that heat often occurs in conjunction with other weather conditions that can collectively become really unpleasant for plants.

Minimal humidity makes otherwise unpleasantly warm weather more comfortable for us, but can desiccate foliage that prefers more humidity. Japanese aralia, fuchsia, rhododendron, split-leaf philodendron and many other plants that should not mind warmth can get roasted if warm weather is also too dry. Because sunlight enhances the process, exposed foliage is much more susceptible to damage. To make matters worse, sunlight is more penetrating through clear dry air.

Wind that makes us feel a bit cooler in warm temperatures can likewise cause desiccation as it draws more moisture from foliage. Finely textured plants like Japanese maple, many ferns and some grasses, are particularly susceptible. Offshore wind, like the famous Santa Anna Winds of Southern California, are the worst, because they come in both hot and dry from more arid inland areas, combining all three factors of minimal humidity, heat and wind.

Many of the plants that are susceptible to damage from heat happen to be tropical or subtropical plants that typically enjoy heat as long as the air is humid and still. Others are ‘understory’ plants that naturally live in the shelter of higher trees, so do not like direct sun exposure or wind. Yet, even substantial trees, like fern pine (Podocarpus spp.) and even redwood, can get a bit roasted if the weather gets hot, dry and windy enough.

Conservation of water makes warm weather even more uncomfortable for sensitive plants. They really want more water to keep their foliage and stems well hydrated. Hosing ferns and grasses when things get really hot helps to cool the foliage, and briefly increase the ambient humidity. Because thin young bark is more susceptible to sun-scald in hot weather, pruning that would expose more bark should be delayed until the weather turns cool again.

Humidity Is The Other Weather

Some delicate foliage prefers more humidity.

It is difficult to always ignore the weather. Regardless of how pleasant it typically is here, it sometimes gets warm or cool. It occasionally gets hot or cold. Rain is wet and perhaps messy. A breeze is comforting while the weather is warm. Strong wind can be damaging. However, humidity is one major component of local weather that gets little consideration. 

Humidity gets more consideration in climates that are either uncomfortably humid or arid. Some parts of Florida get famously humid and hot simultaneously during summer. Some flora and insects enjoy such weather. Unfortunately for the rest of us, humidity enhances the already unpleasant heat. Locally, hot or warm weather is rarely bothersomely humid.

Similarly, local weather is rarely unpleasantly arid (lacking humidity). This is a chaparral climate, which is ‘semiarid’. Relatively minimal humidity makes heat a bit more tolerable than it would be with more humidity. Yet, humidity is generally sufficient to sustain foliage that would desiccate in a more arid desert situation. Actually, this is an excellent climate.

Although, it is not perfect. Flora and fauna have different standards for exemplary climate and weather. The relatively minimal humidity that makes uncomfortably warm weather a bit more tolerable for people and animals is much less appealing to some plants. Except for those that are native to desert or chaparral climates, most plants prefer more humidity.  

Many popular plants are understory plants, that naturally live in the partial shade of taller vegetation. With shelter from desiccating arid wind and harsh sunlight (to enhance heat), most do not mind heat. Otherwise, foliage might roast. Those with finely textured foliage, such as astilbe, ferns, grasses and some Japanese maples, are particularly susceptible.

Some tropical and subtropical plants, such as split leaf philodendron and fuchsia, prefer to be understory plants here, even if they would prefer more exposure within their natural ecosystems. The shelter provided by more resilient vegetation compensates for deficient humidity. Furthermore, adequate irrigation promotes healthy hydration of delicate foliage. 

Too Much Of A Good Thing

Healthy growth can overburden tree limbs.

It was probably the extra chill this last winter that made some deciduous fruit trees bloom more profusely early in spring than they typically do. Unusually busy bees in some regions improved pollination and subsequent fruit set, although some was dislodged by late rain. The sudden warmth this last spring not only improved the flavor of fruit, but also made some grow larger than typical.

More and better fruit is usually what those who grow fruit strive for. The problem with some trees now is excess. After pruning our fruit trees every winter for a few years, we get to know how much to prune them to maximize productions without overloading the trees. When the trees produce more than expected, they may not be able to support the weight of their own fruit.

Many plum and peach trees have already dropped limbs that were overburdened with the weight of fruit. Nectarine, apricot, pluot (and aprium, plumcot and all those weird hybrids), and prune trees can potentially drop limbs as well. Even without breaking, heavy limbs can get disfigured simply by sagging downward. Broken or sagging limbs expose inner bark to sun scald.

Broken limbs obviously can not be salvaged, so can only be removed. They should be cut cleanly away without leaving stubs. Sagging limbs can be propped with notched stakes tucked under side branches that will keep them from sliding upward. The notches keep such stakes from sliding off to either side. Much of the excessive fruit can be removed from severely sagging limbs. However, if the fruit is so ripe that it will not be getting any heavier, there is no advantage to removal.

Formerly shaded bark that suddenly becomes exposed to direct sunlight should be shaded. If partly shaded though much of the day, it should be safe. If expected to be shaded next year by new growth, bark can be protected temporarily with duct tape or stapled cardboard, or even foliated bits of the limb that broke, tied over the bark. Light colored paint is unsightly, but can be applied to reflect sunlight from bark that is expected to remain exposed permanently.

Excessive weight is not only a problem for fruit trees. Some sweetgum, fruitless mulberry and old fashioned Chinese elm trees can produce so much healthy foliage that limbs hang lower than they should. Some shade trees can even drop limbs ‘very’ unexpectedly, when the weather is warm and humid, but without wind.

Perennial Plants Perform For Years

Perennial pea is similar to sweet pea, but as the name implies, it is perennial.

‘Perennial’ is a simple adjective that describes something that last for more than a single year. Horticulturally, it is not this simple. After all, every plant that is not an ‘annual’, which completes its entire life cycle within only one year, is technically a ‘perennial’. Those that develop lignified (woody) parts instead conform to such categories as tree, shrub or vine.

Even these categories are not as simple as they seem to be. Palms are trees, but without woody stems. Technically, they are merely very large perennials. Some consider them to be ‘herbaceous trees’. Yucca trees conform to the same category; while terrestrial yuccas are usual perennials. Sweet peas are annual vines. Perennial peas are perennial vines.

Many annual bedding plants, such as begonia, chrysanthemum, primrose, cyclamen and even busy Lizzie, are technically perennial. They could survive for a few or several years if they get such a chance. All ferns, including tree ferns, are perennials. So are bamboos, ornamental grasses, and many succulents. ‘Biennials’ are perennials that live two years.

Many of the most popular perennial plants have an indefinite life span. It is impossible to know how long they can survive. They are constantly replacing themselves with new but genetically identical parts. For example, bearded iris migrate and propagate by rhizomes that could have been propagating for centuries. New plants are identical to their original.

However, many perennial plants with potential to propagate indefinitely might eventually get shabby. New Zealand flax, after many years, may slowly migrate outward from where it started growing, leaving a bald spot in the middle. Outer shoots relocate easily to patch such bald spots, or unite as a fresh clump. Crowded lily of the Nile benefit from thinning.

Bulbs and bulb like plants are generally perennial, even if unreliable as such in the mild local climate. (Many bulbs and bulb like plants prefer more chill through winter than they get here.) Most of these sorts of perennials are dormant for part of the year, so die back to the ground. Hostas are bare through winter. Florists’ cyclamen are bare through summer.

Perennials provide foliage and bloom

Bloom can repeat in season perennially.

Does anyone really know what a ‘perennial’ plant is? It is obvious that it is not an ‘annual’ plant that lives only a single year. A ‘biennial’ plant produces vegetative (non-blooming) growth in the first year, and then blooms, develops seed, and dies in the second year. A plant only needs to live more than two years to be a perennial plant, or simply a ‘perennial’. Well, that does not narrow the definition down much. Bristlecone pine can live for thousands of years, but is not often thought of as a perennial.

In simple home gardening terminology, a perennial not only lives for more than two years, but does so without producing significant woody stems. Yes, this also happens to include palms and trunk forming yuccas (which are known as ‘perennial trees’), but that is another topic. Some perennials live only a few years. Some can live indefinitely by replacing their stolons, rhizomes, bulbs, tubers or whatever they regenerate from as their old growth gets left behind.

For example, bearded iris spread by fleshy stems known as ‘rhizomes’. As they grow from the forward tips, the older ends that get left behind will rot away. They are constantly replacing themselves, without leaving evidence of how long they have been doing so. (In other words, it is impossible to cut one down to count the rings.)

Many plants that are known as annuals are actually perennials, but get removed and replaced during their respective dormant season. Busy Lizzy can regenerate each spring if their roots do not succumb to frost in winter. Begonia, chrysanthemum, cyclamen and primrose are just some of the many other annuals that could technically survive as perennials.

Lily-of-the-Nile, African daisy, daylily, canna, penstemon, New Zealand flax and various grasses and ferns are some of the more familiar perennials. They are too diverse to generalize about, but happen to be among the most reliable of plants for bloom and foliage. Because form and mature size is somewhat predictable, properly selected perennials are unlikely to outgrow their particular situations.