Category Archives: Garden Advice

Can Flowers Tell Time?

Most gardeners quickly realize that not all flowers bloom at the same time. Not only do they bloom during different parts of the season, many bloom at different times of the day.

You may have noticed a few names in our catalog that hints at this pattern, like Morning Glories, Evening Primroses, and Four O’clocks. We also have heliotropic flowers like sunflowers that follow the sun as it moves across the sky during the day.

So why do these flowers bloom this way, and how do they know when to bloom? Can plants tell time? In this post, we’ll dive into how these plants operate.

Circadian Rhythm 

You may have heard of a circadian rhythm in relation to human beings. In simple terms, it’s our internal clock that functions on a 24-cycle and regulates our alertness and sleepiness by responding to changes in light and our environment. 

So, what does this have to do with plants? Researchers have found that plants have circadian rhythms, too. This biological clock regulates processes like photosynthesis, stomatal movement, and, in many cases, flower formation and opening. Some plants even use their circadian rhythm to time preparations for attacks by daytime active pests!

So Why Bloom at Different Times?

Despite plants having a functioning circadian rhythm, not all flowers open at the same time of day. This is because there are advantages to blooming at specific times.

Purple Morning Glory bloomsMorning Glories, Spiderwort, Daylilies, and other Daytime Blooms

There are several flowers like morning glories, spiderwort, and daylilies with blooms that open just a single time. Many of these, like morning glories, open when they’re hit by the sun in the morning. You may have noticed that if you plant morning glories in shadier areas, they may not open until later in the day. 

These flowers take advantage of daytime pollinators like bees and butterflies. Morning glories, specifically, co-evolved with Morning Glory Bees (Cemolobus ipomoea), which are thought to be most active in the morning!

Tina James’ Magic Evening Scented Primrose
Tina James’ Magic Evening Scented Primrose

Four O’Clocks, Moonflowers, Evening Primroses, and Other Evening and Nighttime Blooms

While many flowers bloom during the day, others open in the evening. These night owls aren’t confused; they’ve evolved to take advantage of nocturnal pollinators. Worldwide, bats and moths take the night shift, pollinating a number of plant species. 

Around here, most of these flowers, including those listed above, are primarily pollinated by the Sphingidae family of moths, commonly called hawkmoths or sphinx moths. This family includes about 1450 species of moths with long tongues and the unique ability to hover while pollinating flowers. This hovering has evolved only in a few other species: hoverflies, certain bats, and hummingbirds. Hawk moths hover so well that they’re often mistaken for small hummingbirds!

Why Do Sunflowers Move?

Sunflowers, on the other hand, stay open longer than all of these flowers but move each day! What’s up with that?

Sunflowers are the poster children for plants with heliotropism (directional growth in response to sunlight)  and circadian rhythm. Each day, they track the sun across the sky, starting facing the eastern sunrise in the morning and finally facing the western sunset in the evening. 

It goes further than that, though. Not only do they respond to the sun, they anticipate it. As the sun sets each night, the plants face west, but overnight, they slowly move to face east in anticipation of the morning sun. 

Researchers say that the plant’s circadian rhythm times this movement, while the plant’s growth rate controls the actual movement. Scientists discovered that growth rates on the plant’s east side were high during the day and low at night, while the growth rates on the plant’s west side were high at night and low during the day, resulting in the plant turning.

 

We can learn so many fun, odd, and exciting things from a garden! Our flower’s adaptations to the world around them are just one of many factors we’re beginning to understand, but there’s so much more we don’t know. We should always keep growing and learning. 

Pinch Plants for Better Production

Summer is a busy time for gardeners. Weeding, watering, harvesting, preserving, and succession planting fill our days. It’s beautiful to watch a garden flourish under your care! Another task you can do while working out in the garden is pinching certain plants. Pinching plants is quick and easy and can make a big difference in their growth habits. Learn to pinch plants successfully.

What is Pinching?

Pinching is a type of pruning or harvesting that encourages lateral growth in plants. All you need to do is pinch off the tip of the plant or the end set of leaves or buds just above the node or bulge. Often, you’ll see small sets of leaves or buds just below where you need to pinch. When you do this, the plant sends out a set of lateral branches. Usually, you can do this just with your thumb and pointer finger, but you could use a small pair of snips if that’s easier. 

Failing to pinch your plants isn’t the end of the world. They’ll still grow fine. However, it’s a great way to encourage a bushier growth habit, resulting in increased harvests for certain herbs, more blooms on specific flowers, and fewer chances of lodging. 

Pinching can be nerve-wracking! Should you really hack the top off of a seedling? Yes! It’s intimidating but worth it if you want bushy, productive herbs and flowers.

Cactus-Flowered Zinnias (Zinnia elegans)
Cactus-Flowered Zinnias (Zinnia elegans)

Can I Pinch Any Plant?

Only some plants benefit from pinching. Whether or not you should pinch a plant depends on the species and their growth and fruiting habits. Below are a few of the common plants that 

Flowers to Pinch

  • Calendula
  • Cosmos
  • Salvia
  • Sweet William
  • Zinnias

Herbs to Pinch

  • Basil
  • Lemon Balm
  • Mint
  • Oregano
  • Rosemary
  • Sage
  • Thyme

Plants Not to Pinch

While some plants benefit from pinching, others should never be pinched. For some plants, like those listed below, pinching can be detrimental and damage flowering or production.

  • Cockscomb
  • Delphinium
  • Dill 
  • Foxglove
  • Larkspur
  • Sunflowers

When to Pinch Plants

Pinching works best when you catch the plants at the right time. Ideally, it would be best if you pinched them when they’re between 12 and 18 inches tall and are often starting to look a bit leggy.

You may only need to do this once or twice for flowers like zinnias. For herbs like basil and mint, it’s easy to maintain this practice as a harvesting method. As you’re not growing the plants for flowers but rather foliage, we don’t need to worry about preventing blooms. We can pinch above the nodes each time we harvest.

Other Pruning Methods

Pinching isn’t the only method of removing material from plants. Here are other ways to alter plants to change their shape, encourage production, or improve their health.

Deadheading

Another way to encourage continued blooming is by deadheading spent flowers. Popping spent blooms off plants like marigolds, zinnias, and cosmos can encourage them to put more energy into repeat blooming rather than forming seeds.

Pruning

Pruning generally refers to clipping off larger branches. Pruning can be done for various reasons. People often prune perennials like fruit trees to remove dead or damaged branches or change their growth habits.

We often prune tomatoes. We prune suckers or non-fruiting branches to make the plants easier to trellis, improve air circulation, and encourage production. 

 

Pinching the tops of your seedlings may seem like a terrible idea. No one wants to damage a plant they have tended. However, pinching is a great way to encourage blooming, production, and health in many flower and herb species. Try pinching your plants this season!

Protecting Crops from Heat Stress

This week, major heat waves are hitting much of the East Coast and Midwest. We hope everyone finds a cool place to rest and stay safe this summer. However, we also realized that many gardeners are probably struggling with heat stress in their plants during this time. While we can’t move our whole garden into the air conditioning, we can do a few things to help protect our crops from extreme temperatures.

Check Plants Often

Keeping an eye on your plants and spending some time in the garden whenever it’s cool enough, like early mornings or late evenings, can help prevent stress and catch any issues early.

One thing you want to keep on top of even though it’s tough in hot weather is weeding. Weeds often compete with crops for moisture and may prevent adequate air circulation.

You should also harvest often. Picking crops before they are overripe will prevent plants from wasting energy. 

You should also watch for signs of heat stress, such as fruit or blossom drop, curling or yellowing leaves, and wilting. If you see these signs, consider taking some of the steps outlined below. 

Maintain Proper and Consistent Watering

Consistent moisture is essential for good production and plant health, especially during high temperatures. Inconsistent watering can result in heat stress symptoms like curled leaves, poorly formed cucumbers, splitting tomatoes, and more. 

Ideally, you should water in the early morning or evening. If you water during the middle of the day, much of it will be lost to evaporation.

How you water also matters. Overhead watering leads to much more evaporation than directly watering the soil around plants. If possible, use soaker hoses or drip irrigation. For small gardens where you hand water, try to direct the water to the base of the plant. 

Especially during hot weather, deep watering can be helpful. Aim to water at least two to three times per week, getting a total equivalent of about 1 inch of rainwater to your crops weekly.

Generally, it’s tough to provide too much water during hot weather, but keep an eye on your soil and avoid overwatering. Soggy soil can lead to root rot and fungal diseases.

Container plants will dry out much faster and need extra attention and watering. 

woman using scythe with greens and onions growing in the foreground
Wood chips make great mulch for preventing heat stress and you may be able to find them for free.

Mulch

We talk about mulch a lot on this blog, but it really can make a big difference when it comes to heat stress. A few inches of mulch, such as straw, pine needles, old leaves, grass clippings, or wood chips, can decrease soil temperatures dramatically. It also helps block weed growth and keeps the soil moist.  

Further, mulch can prevent soil from splashing onto the leaves of crops like tomatoes, which are highly susceptible to soil-borne fungal diseases like late blight. 

Provide Shade to Prevent Heat Stress

While plants need a certain amount of sunlight to grow, they’re generally too stressed during the hottest parts of the day to do much growth anyway. Providing some temporary shade, particularly during the afternoon, can be helpful.

For small gardens, you may be able to use what you already have on hand. Consider using patio umbrellas, EZ Up canopies, or shade sails to offer your plants some temporary respite from the afternoon sun. 

Alternatively, you can purchase shade cloth or row cover and use it over plants. We often use row cover at SESE to keep out pests, provide shade for cool weather crops, and provide a little frost protection for fall crops. Old sheets or other materials and scrap pieces of fencing could be used for a similar effect.

If possible, move container plants to where they will receive morning sun and a period of afternoon shade. 

Avoid Fertilizing

When gardeners see plants looking rough from heat stress, they sometimes mistake the signs for a nutrient deficiency.  Unfortunately, fertilizer does more harm than good during periods of extreme heat. 

A boost in nitrogen and other nutrients signals to plants that it’s a good time to put on new leaf growth. We don’t want plants that are already overtaxed from the heat trying to make new leaves! Focus instead on watering, weeding, and harvesting to improve plant health.

Case Knife Pole Snap Bean
Case Knife Pole Snap Beans are less susceptible to heat stress than some varieties.

Plan for a Heat Stress Resistant Garden Next Season

If heat stress is a major struggle for you this season, it’s a good idea to incorporate that into next season’s garden plan. Maybe you need to keep more mulch on hand, invest in soaker hoses, improve the soil, or focus on more heat-tolerant crops. 

Improving your soil can help it hold moisture better. To do this, you need to add organic matter. Cover cropping is a great option, as is adding mulch and several inches of finished compost whenever possible.

Even among cool-season crops, some varieties are more heat tolerant than others. Here are a few of our favorite varieties for when temperatures soar:

There are many other great options. When selecting your favorite crops, do some digging and check for varieties that mention heat and drought resistance. In our catalog and on our website, you can see varieties with a sun symbol. This means that they are especially adapted to the Southeast. 

Keeping your garden healthy and productive during heat waves can be a major struggle. Using these strategies when the temperatures climb can help you keep your garden in top shape during the hottest summer months.