Slow Growth? No Flowers?
Look to the simplest solutions first
There are so very many things that can cause a plant to lose vigor, fail to thrive or fail to bloom. Once you are aware of the possible causes you will likely see that solutions are simple and evident. We know of course that all plants have basic needs for water, nutrition and air. Growth problems nearly always have something to do with those needs not being met properly. And of course, different plants have different needs, so be sure you first understand what your plants require and prefer. Once armed with that information, diagnosis is much easier. Observation of how environmental conditions have changed to affect growth will also be necessary.
It’s all simpler than it sounds. Following are some of the most common problems and conditions that may cause your plants to stop growing and blooming.
The very first thing you need to do is carefully select plants that are recommended for your zone and specific region. Poor selections often fail. Once you become experienced, experimenting with new, exotic or marginally hardy plants in protected areas of your landscape can produce many failures, but also satisfying successes. Until then, stick to the recommendations of a trusted local garden center.
Whether from watering or rain, saturated soil essentially suffocates plant roots. Excess moisture that cannot be absorbed into the soil, used by the plant, or allowed to drain away will fill all the air gaps between soil particles. Without air gaps the roots are unable to take in oxygen and will eventually rot in the saturated soil. Occasional over watering or periods of rain generally will not cause too much problem, but if the conditions persist the plants will suffer.
Even if wet conditions are not persistent, over watering can encourage excess and weak top growth with a poor root system. Be sure you understand the moisture needs of your specific plants.
Not enough moisture will quickly affect the appearance of your plants. Wilting of the foliage may prompt you to provide water, but if the plant is repeatedly deprived of sufficient water it will restrict its’ own growth and stop using resources to produce blooms to try to save itself. Excessive heat may increase a plants’ need for water. All your plants should be carefully monitored in periods of drought.
Foliage color may fade to pale or gray green if water is limited for long periods. Again, understanding the moisture needs of your specific plants will help to resolve or prevent the problem.
Even experienced gardeners can be over optimistic about the amount of sunlight a garden plot actually receives. Plants that require full sun need to receive at least 6 hours of direct sunlight in order to thrive and bloom to their full potential. Part shade plants need 4 hours of sun, but not in the heat of the day. Sunlight is essential to the flowering process, although each plant type requires different amounts of sun to produce blooms.
The time of day plants receive sun can also be very important. In some cases you may see specific recommendations for a plant of only morning sun. In morning sun the plants will receive all the benefits of direct sun without any heat stress. Some plants love the heat and will be healthy and full of blooms in all day sun and heat. Be sure you know your plants’ preferences.
Nutrition for plants is a huge subject and can get complicated and involved if you have unusual soil conditions, are growing plants with unusually fussy needs or even somewhat for growing edibles. But generally your common garden plants need some pretty standard food. That can be balanced garden fertilizer or compost either purchased or homemade. If your plant looks weak and sickly or the foliage starts to yellow and blooming is reduced or stops, likely it needs a bit more food. If the plant and foliage is richly colored and lush but without blooms, it has likely been over fed.
Some plants are heavy feeders, and some prefer little or no nutrition. With the knowledge of your plant needs, follow fertilizer instructions carefully. High nitrogen fertilizers are generally best avoided, opting instead for a good balance of NPK. Compost or composted manure can be worked into the soil or top dressed to allow plants to take the nutrition is needs slowly and consistently.
Both high and low temperatures can cause a plant to stop growing or flowering. Excessive heat can dry out soil, stress plants and sometimes disrupt bloom cycles. Typically a plant will stop growing because it is having difficulty recovering repeatedly from the heat of the days if the nights also stay very warm. Prolonged heat may cause a plant to fail to thrive or prematurely set seed to propagate itself and then die.
Low temperatures simply slow down the processes of the plant, however frost or freeze can damage flower buds and damage or kill the plant.
Depending on the age of a plant, a young plant is simply just not ready yet to bloom. Sometimes it takes 2 or three years for a plant to mature enough to bloom and flourish.
Plenty of space for root growth allows for good plant growth and flowering. Without plenty of root space plants will stop growing as they need adequate root systems to deliver food and water. Tightly packed plants are also competing for available nutrients and moisture and likely unable to all get enough of everything.
Overcrowded plant foliage will also reduce air circulation and cast shade on each other. These two conditions can inhibit growth as well as invite and encourage disease. For most plants the leaves of neighboring plants should not touch each other at full growth. Some plants do better with crowding than others, especially those with deep rooting ability.
How you prep and plant can sometimes have a marked affect on blooming. For example peonies need to be planted at a precise depth or they may not produce a single bud. Bulbs also need to be planted at certain depths for best blooming. There are also other details for some plants that you need to pay attention to, for example “eyes” up, “nose up”, roots down. Be sure you understand the requirements of your specific plants.
If you are growing plants in a container, overcrowding has an easy fix. If the plant or plants were getting very large compared to the container and then stopped growing, it is very likely the roots have filled the pot and can no longer grow to support plant growth. Transfer the plants to a larger container and next year, either acquire large pots or put fewer or smaller plants in the pot.
Deadheading and Pruning
Many flowering plants need the spent blooms removed in order to continue producing fresh blooms. If you have more dried up and dead flowers than fresh ones, it is time to deadhead.
Flowering shrubs often need pruning in order to bloom each year or repeatedly in the season. It is crucial that you know when to prune or you may completely prevent flowering. A flowering shrub may produce blooms only on new growth, only on old growth, or both. Find out exactly when to prune your specific plants.
Most perennials require periodic division to keep the plant vigorous and blooming, generally every 2 to 5 years. Find out how and how often your plants should be divided.
Allowing weeds to thrive will rob your plants of water, nutrients and space. Weeds are often very aggressive and if allowed, crowd your plants right out of the garden.
Disease and Insects
Damaging insects are usually easy to spot and then identify, disease is a bit more difficult, requires careful observation and some searching for information. The sooner you can remedy the situation the better chance your plants will have to recover.
Stress can sometimes be one of the trickier problems to diagnose because a plant showing signs stress is really a symptom. Stress is most commonly caused by heat and usually quickly displays dramatic symptoms. But there are many things that can create stress for your plants. Some of the issues that cause stress have already been discussed and can be diagnosed by a specific issue, need or deprivation, such as water and nutrients, heat and drought, disease or overcrowding.
Try not to worry to much about slow growth, no growth, or no flowers. Be patient and watchful. You may need to let nature take its’ course sometimes without much intervention.