There's an art to placing flowers in the home, and these precautions should be kept firmly in mind

Placing a few flowers indoors can add a warm atmosphere and benefit physical and mental health. But many people mistakenly think that the more flowers the better, and without being selective, blindly nourish them, turning a small room into a blaze of blossoms. Yet they never imagine that beautiful flowers can also harm human health. Green plants, in the process of metabolism, also carry out photosynthesis and respiration. Photosynthesis must take place under a certain light intensity, equivalent to the light intensity of a 250-1000 watt incandescent lamp on a surface 1 meter away. When light is insufficient, plants mainly carry out respiration rather than photosynthesis; the plants continuously take in oxygen and release carbon dioxide. If too many flowers bloom indoors, the indoor carbon dioxide concentration will increase, especially at night, when plant respiration is very vigorous; add to that poor indoor ventilation and the carbon dioxide concentration becomes fairly high, and over time this will affect the body.

Sleep experts point out that placing plants indoors is bad for people's sleep at night, because at night plants release carbon dioxide, creating a situation in which they compete with people for limited oxygen. With less oxygen, sleep is naturally affected.

For flowers placed indoors, it is best to choose plant varieties that can absorb harmful gases, such as spider plant, chrysanthemum, pomegranate, orchid and scarlet sage.

There are also some flowers that are not suitable for placing indoors, and this should raise alarm.

1. Flowers with a certain peculiar odor or strong fragrance: such as pines and cypresses, which secrete resinous substances and release a fairly strong turpentine scent; smelling it for a long time can lead to reduced appetite and nausea. The heavy, gloomy odor of peony can make a person listless, weak and short of breath. The fragrance of night-blooming jasmine and tulip is so strong that being in such a scent for a long time is unbearable. Famous flowers such as narcissus and rose have an assaulting fragrance, and over time, especially when breathing in these floral scents during sleep, they can also make a person uncomfortable.

2. Flowers that can cause allergic reactions: such as Chinese rose, sweet viburnum, lantana, hydrangea, geranium and redbud, all have allergenic properties; if you touch or stroke them, they often cause skin allergies. In severe cases, red rashes appear, with unbearable itching.

3. Flowers with toxins, such as the cactus family, mimosa, poinsettia, oleander, yellow azalea and dracaena, absolutely must not be placed indoors. Folk call lucky bamboo "dumb stick," and there is a saying, "The flower is lovely to look at, but the poison is hard to bear." Botanists have determined that it contains some toxic enzymes (commonly known as dumb-stick enzymes). Its stem and leaf sap, when it touches the skin, is strongly irritating; if an infant accidentally bites it, it can cause swelling of the throat and even paralyze the vocal cords and cause loss of voice.

In addition, some ornamental flowers such as crown-of-thorns, red-backed osmanthus, croton, firecracker plant and golden fruit olive contain cancer-promoting substances that can induce nasopharyngeal cancer and esophageal cancer. It seems that growing flowers at home also has its rules.