What's wrong with my pine trees dropping needles?

My neighbor showed up on my doorstep, panicked about his pine tree. He brought a picture which showed needles changing color and falling off. What was wrong with the tree, was it dying? Looks scary, huh?

Homeowners will often see their needles on evergreen trees turning brown and falling off in the late summer or fall and become alarmed. Needle drop on pine trees is a naturally occurring phenomena. If pine needles turn brown from the interior of the tree, and the outer needless stay green, there is no cause for alarm.

Most people know that deciduous trees such as cottonwoods, oaks, or maples lose their leaves in the fall, but fewer people understand that evergreen trees also lose their old needles in the late summer or fall. Needle age at which drop occurs varies among evergreens and within species. Eastern white pine loses 2-year old needles. On the other extreme, bristle-cone pine sheds needles that are 14-17 years old.  If there is die-back or yellowing on the tips of branches or needles, there may be a problem. Consider drought, salts, root damage, herbicide damage, soil compaction, insects, or other factors. 

Occasionally, 'deciduous conifers' such as the bald cypress, larch, and dawn redwood are found in Idaho landscapes. 

These conifers all lose their needles every autumn, to be replaced the following spring. 

   Don't lose hope - it's normal!!! 

Chill Out! Cold Stratification for Native Plants

 

Cold stratification is an important step for growing many native plants in USDA Hardiness Zone 7. This process mimics winter conditions, helping seeds break dormancy and ensuring they germinate at the right time in spring. In the Treasure Valley area, which is situated in Ecoregion Level III 12 (Snake River Plain) and borders Ecoregion Level II 10.1 (Cold Deserts), you have a unique opportunity to cultivate a variety of native plants. Whether you’re interested in wild sunflowers, asters, goldenrods, lupines, purple coneflowers, milkweed, or penstemon, following these steps will help you successfully propagate these beautiful species in your garden.

Understanding the Ecoregion

Ecoregion 12 features a mix of desert and semi-arid environments, characterized by cold winters and warm, dry summers. The region's soils vary from sandy to clayey, which influences the native plant communities that thrive here. Plants in this area have adapted to withstand drought and temperature extremes, making them well-suited for home gardens that aim to support local wildlife and conserve water.

Starting Seeds Indoors or in a Greenhouse

Starting your native seeds indoors or in a greenhouse allows you to control conditions better. Follow these steps:

1. Gather Your Seeds: Collect seeds from native plants in the fall, ensuring they are fully mature and dry.

2. Prepare Your Pots: Use seed-starting pots filled with a seed-starting mix. Make sure the pots have drainage holes.

3. Moisten the Medium: Lightly moisten the seed-starting mix so it's damp but not soggy.

4. Cold Stratification:

• Option A: Directly in Pots: Sow the seeds in the pots, covering them lightly with soil only if they don’t require light to germinate. If they do need light, surface sow seeds and place the pots in the refrigerator for 4-12 weeks. Keep the pots in a plastic bag to retain moisture.

• Option B: Pre-soaking: Alternatively, mix seeds with a moist medium like sand or peat moss in a zip-top bag, refrigerate for 8-12 weeks, and then surface sow them in pots after stratification.

5. Move to Light: After the stratification period, move your pots to a well-lit area or greenhouse. Ensure they receive plenty of light but avoid direct, harsh sunlight at first.

6. Water Regularly: Keep the soil consistently moist (but not waterlogged) as the seeds begin to germinate.

7. Transplanting: Once the seedlings have a few true leaves and the danger of frost has passed, transplant them into your garden or larger containers.

Starting Seeds Outdoors in your garden or raised beds

1. Gather Seeds: Collect seeds in the fall from mature plants, ensuring they are fully dry. This timing allows you to utilize natural seasonal changes for germination.

2. Prepare the Planting Area: Choose a well-draining spot in your garden or raised beds. Loosen the soil and remove any weeds or debris.

3. Surface Sow: Scatter the seeds on the surface of the soil. Many native seeds benefit from light exposure to germinate, so avoid covering them deeply. If the seeds require some soil coverage, lightly sprinkle a thin layer of soil over them.

4. Watering: Gently water the area to help settle the seeds into the soil without washing them away. Ensure the soil stays consistently moist, especially during dry spells.

5. Winter Conditions: As winter arrives, the seeds will experience natural cold stratification, which helps break dormancy and prepares them for germination.

Benefits of Cold Stratification By cold stratifying your seeds, you help ensure healthy germination and align plants with their natural growing cycles. This process also supports local ecosystems by enhancing biodiversity, stabilizing soil, and conserving water.

With a little preparation, you can successfully cultivate beautiful native plants that thrive in your region, including wild sunflowers, asters, goldenrods, and lupines. 

Happy gardening!

A Purrfectly Wicked Reputation

A black cat crosses your path. Do you turn around? Knock on wood? Or simply wonder where it's headed?

For centuries, black cats have been blamed for everything from bad luck to witchcraft. They've been accused of casting spells, bringing misfortune, and keeping suspicious company.

All this from an animal that spends roughly half its life sleeping and the other half pretending it hasn't been fed.

So how did black cats get such a spooky reputation?

In medieval Europe, black cats became associated with witches. Some people believed witches could transform themselves into cats, while others thought the animals served as magical assistants, known as familiars.

Imagine being a perfectly ordinary cat, minding your own business, only to discover the entire village thinks you're practicing witchcraft.

Talk about bad publicity!

And if that weren't enough, stories of winged cats added another twist to feline folklore. These mysterious creatures, sometimes described as cats with batlike wings, sound as though they wandered straight out of a witch's spellbook.

A Bat Cat? Apparently, four paws and nine lives weren't mysterious enough!

But here's where the story takes an interesting turn.

Not everyone thought black cats were trouble.

In Scotland, a black cat arriving at your doorstep was traditionally considered a sign of prosperity. Japanese folklore has also associated black cats with good fortune. And sailors sometimes welcomed black cats aboard their ships as lucky companions.

Apparently, whether a black cat brings good luck or bad luck depends largely on where it happens to be walking.

The cat, of course, couldn't care less.

And what about Halloween?

By the time Halloween decorations became popular, black cats had found their permanent place alongside witches, broomsticks, and jack-o'-lanterns.

Vintage Halloween decorations from the early 1900s featured plenty of arched backs, glowing eyes, and mysterious black silhouettes.

Yet there's something rather wonderful about a creature once feared for its supposed supernatural powers becoming one of Halloween's most beloved symbols.

And perhaps black cats really do possess a little magic.

They can appear out of nowhere, vanish without a sound, see things we can't, and convince perfectly sensible humans to serve them dinner on demand.

Coincidence? We think not.

So, on October 29, National Cat Day, give those mysterious black felines a little appreciation.

And if a black cat crosses your garden path this Halloween, don't worry about bad luck.

It's probably just checking whether you've planted any fresh catnip.

Happy National Cat Day!

https://www.aaa.si.edu/blog/2017/10/the-good-the-bad-and-the-black-cat

Green Is So Last Season

Every fall, green leaves turn shades of yellow, orange, red and purple. It may look like the trees are putting on one last show before winter, but what we are really seeing is plant chemistry at work.

During spring and summer, leaves are dominated by chlorophyll, the green pigment essential for photosynthesis. Chlorophyll absorbs light energy that plants use to turn carbon dioxide and water into sugars. There are other pigments in the leaf all along, but the abundance of chlorophyll masks
many of their colors.

As autumn approaches, shorter days and cooler temperatures signal deciduous trees that winter is coming. The tree begins preparing to shed its leaves. Chlorophyll production slows and eventually stops, while existing chlorophyll breaks down.

As the green fades, pigments that were there all summer finally become visible.

Carotenoids produce yellow, gold and orange colors. These pigments help plants capture light and protect leaf tissues from excess light during the growing season. They are responsible for the yellow of aspens and the golden-orange colors seen in many other trees. Carotenoids are also what give carrots their orange color.

Red and purple fall colors work a little differently

Anthocyanins produce reds, purples and crimson shades. Unlike carote
noids, which are already present in the leaf, many anthocyanins are produced in late summer and fall. As the tree prepares to close off the connection between the leaf and branch, sugars can become trapped in the leaf. Bright, sunny days encourage sugar production, while cool—not freezing—nights slow the movement of those sugars out of the leaf. Under the right conditions, anthocyanin production increases.

That helps explain why fall color can be spectacular one year and less impressive the next.

Weather matters. A succession of sunny days and cool nights can favor brilliant reds. Drought, an early hard freeze, prolonged warm weather or storms that strip leaves from trees can shorten or dull the display

Eventually, the tree forms an abscission layer where the leaf stem joins the branch. This layer gradually cuts off the movement of water and nutrients. The leaf falls, leaving the tree better prepared to conserve resources through winter.

So when you see a tree changing from green to gold, orange or crimson, you aren't simply watching leaves “die.” You're seeing chlorophyll disappear, other pigments revealed or produced, sugars shift, and the tree carefully shut down a leaf it no longer needs.

Fall color is beautiful—but it is also a pretty impressive chemistry lesson happening right over our heads.

https://extension.illinois.edu/blogs/flowers-fruits-and-frass/2025-10-21-science-and-splendor-fall-foliage

https://www.fs.usda.gov/visit/fall-colors/joy-and-science

Jams, Jellies, Marmalades - Yummy!

 Fresh, spreadable fruit in the form of jam, jelly, preserves, or marmalade, might possibly be summer's sweetest reward. The best part is that they are easy to make and can be enjoyed long after you put your garden to bed. So, what is the difference between each of these spreadable options? 

Before we dive in, it helps to know that there are two main factors that turn fruit into a thick, spreadable texture: heat (from cooking) and pectin. When fruit is heated, it will lose liquid, causing the fruit to reduce to a firmer state. Pectin is naturally-occurring in fruit and happens to also make fruit thicken when cooked. However, not all fruit contains enough pectin to reach a firm texture, so many spreadable fruit recipes call for additional pectin.

Jelly:
Jelly is the firmest and clearest of the sweet, spreadable options. The fruit is cooked and strained so only the juice ends up in the final product. Jelly is so firm that you could turn the jar over and slide the jelly out in one solid piece.

Jam:
Jam is a chunkier version of jelly. Jam has more fruit pieces and is slightly looser in texture. Chopped or pureed fruit is cooked with sugar, so pieces of fruit end up in the final product. Jams are not clear and not solid like their jelly cousin. Here's a video for strawberry freezer jam!

Preserves:
Preserves are like jam but contain more and bigger pieces of fruit. Preserves have the least gel-like consistency. They are great for serving with cheeses and meat dishes.

Marmalade:
Marmalade is a preserve, but it is made only with citrus. The whole fruit, rind and all, create a bitter-sweet spreadable delight. Lemon, orange, and grapefruit make great marmalades. Marmalades are aromatic with complex flavors and oils from the citrus peels.

Jam, jelly, preserves, and marmalade start out almost the same, but take different forms depending on how they are processed. Whether you like your fruit a spreadable solid, with small pieces of fruit, with large pieces of fruit, or you want the complex flavors of citrus, there is always something good you can choose to put on your toast. 

What Are All Those Flies in My Fall Garden?

If you’ve noticed an unusual number of large, bristly flies hanging around your flowers this fall, take a closer look before reaching for the fly swatter. They may be tachinid flies, and they are some of the good guys in the garden.

Tachinid flies are a large and diverse family of beneficial insects. More than 1,000 species are found in North America. Depending on the species, they can look a bit like an ordinary housefly—gray, brown or black—but many are noticeably bristly. Some are surprisingly large and robust.

 What makes them beneficial?

It’s what happens during their larval stage that makes tachinid flies important to gardeners.

Female tachinids use other insects as hosts for their young. Some lay eggs directly on a host, while others have different strategies for getting their larvae inside. Once there, the developing fly larva feeds within the host and eventually kills it.

Their hosts can include caterpillars, beetle larvae, grasshoppers, sawflies and true bugs. That means tachinids can help naturally suppress a number of insects we consider garden pests.

The adult flies are much more peaceful. They visit flowers for nectar and can also contribute to pollination. University of Idaho recommends flowering plants as a way to support tachinid flies and other beneficial insects.

Why am I seeing so many in fall?

You may barely notice tachinid flies earlier in the season and then suddenly find them everywhere in late summer or fall. There are many different tachinid species, with different life cycles and hosts, so their numbers and timing can vary considerably.

Late-season gardens can also make the adults much easier to notice. As the number of blooming plants dwindles, remaining flowers become busy gathering places for insects looking for nectar. A successful generation of tachinids developing from insects earlier in the growing season can also mean more adults appearing later.

So a sudden gathering on fall flowers doesn't necessarily mean something is wrong. It may simply mean your garden has provided both the insect hosts and the floral resources these beneficial flies need.

Let them stay awhile

If tachinid flies are visiting your garden, there’s generally nothing you need to do. Keep some flowers blooming as late into the season as possible and avoid unnecessary broad-spectrum insecticides that can kill beneficial insects along with pests.

They may not be as charming as a butterfly or as recognizable as a lady beetle, but tachinid flies are quietly doing some valuable work.

Sometimes a garden full of flies is actually a very good sign.

https://hort.extension.wisc.edu/articles/tachinid-flies/

https://agsci.colostate.edu/agbio/ipm-pests/tachinid-flies/

https://treefruit.wsu.edu/crop-protection/opm/tachinids/

Successful Seed Selection, Saving, and Storage

A successful garden starts with a tiny seed, but selection, saving, and storing these seeds correctly can be much more complicated, and oftentimes overwhelming. This guide will introduce the different seed types and explain effective techniques for saving and storing until they are ready to be planted in the soil.

Types of Seeds

When selecting which type of seeds to plant it is important to understand the different methods of producing the seeds. 

GMO (Genetically Modified Organisms) seeds have been genetically engineered to    introduce specific traits, such as pest resistance or herbicide tolerance. While they offer certain advantages, their long-term environmental and health implications are subjects of ongoing debate. GM seeds are not likely to be found in your home garden because no one sells genetically engineered seeds to home gardeners. GMO crops are expensive, and commercial farmers are required to sign a contract that protects the patented technology. These companies do not sell GM crops to the home garden market or to garden centers.

Hybrid seeds are produced by crossing plants of the same species. Hybrid seeds will potentially have the most desirable attributes of each variety, but they will not remain true to the parent line and therefore are not recommended for seed saving.

Open-pollinated seeds are produced through natural pollination by insects, wind, humans or other natural means. Open-pollinated varieties are well-suited for seed saving and offer a wider range of flavors, colors, and adaptations to local conditions.

How to Save Seeds
Once the plants have grown and fully matured, it is time to harvest and save the seeds. Different procedures apply whether you are collecting “wet” or “dry” seeds. 

Plants with wet seeds include tomato, eggplant, cucumber, melon, squash and pumpkin. These seeds need to be harvested when fruit is ripe and then processed to remove wet pulp or coatings. In order to do this, scoop the seeds out of fully ripe fruit and put them in a glass jar filled with water. Stir the mixture a couple of times a day. The mixture will ferment and viable seeds will sink to the bottom. Finally, pour out the liquid, rinse the seeds and set them out to dry. 

Dry seeds are much easier to save, remove any dirt or debris and spread them out to dry completely. Some of the easiest seeds to save are peas, beans, lettuce, tomatoes and arugula. Always remember to harvest from the healthiest plant with the most desired traits.

Storing Seeds
Store seeds in airtight containers in a cool, dark, and dry location to prevent moisture and oxygen from entering. Label each container with the seed variety, harvest date, and germination rate. Optimal storage conditions for seeds involve low temperatures (around 40°F or 4°C) and low humidity. Avoid exposing seeds to direct sunlight, as this can reduce their viability. It is a good idea to periodically check stored seeds for signs of mold, pests, or deterioration. 

By carefully selecting seeds, you can cultivate resilient and productive gardens in the Treasure Valley. Saving and storing open-pollinated seeds is a rewarding and useful way to contribute economically and sustainably to maintaining your garden.

A Dead Hedge: An Old Idea Worth Bringing Back

What if some of this fall’s pruning didn’t need to leave your yard at all?

A dead hedge is a simple structure made by placing branches, twigs and woody garden cuttings between two rows of upright stakes. Unlike a loose brush pile, everything is contained in a narrow space, creating something that can look surprisingly intentional while providing habitat for wildlife.

And despite its recent popularity in wildlife gardening, the idea isn’t new.

For centuries, people used branches, brush and woven woody material to create barriers around fields and gardens. Early versions served a practical purpose—marking boundaries, controlling livestock and protecting planted areas. Dead hedges were also associated with traditional woodland management, where branches left from cutting and managing trees and shrubs could be stacked between stakes rather than hauled away. Some of those brush barriers eventually collected seeds and supported living vegetation, helping form the hedgerows that became such a familiar part of the British landscape.

Today, the dead hedge has found another job: backyard habitat.

As branches settle and slowly decay, the spaces between them provide cover and protected areas for insects and other invertebrates, while birds may use the structure for shelter, foraging or nesting. The Royal Horticultural Society notes that dead hedges have long been used in managed woodlands and nature reserves and are increasingly being incorporated into gardens.

That doesn’t mean you need a large property.

In a subdivision yard, a dead hedge might be only three or four feet long. Place it along a back fence, beside a shed, behind a garden bed or around a compost area. Drive two parallel rows of sturdy stakes into the soil and layer woody prunings lengthwise between them. Keep the sides neat and trim anything protruding into walkways.Then simply add to it as you prune.

Fall is an especially easy time to start because branches from shrubs, small trees and woody perennials are already part of garden cleanup. Avoid adding diseased plant material, invasive plants that could spread, or anything treated with pesticides that could harm the wildlife you’re trying to support.

For homeowners who like a tidy garden, a dead hedge offers a nice compromise: less material to haul away, a place to put future prunings, and a little more habitat tucked into the landscape.

It may be called a dead hedge, but there can be quite a bit of life inside.

Idaho Native Bitterbrush (Purshia tridentata)

Bitterbrush (Purshia tridentata (Pursh) DC), commonly called antelope bitterbrush, is a native shrub species found throughout much of the Intermountain West and is well established across Idaho. This plant belongs to the rose family (Rosaceae) and is an important component of Idaho’s native plant communities. Bitterbrush is well adapted to dry, semi-arid environments and plays a critical ecological role in sagebrush steppe, a dry grassland ecosystem with low rainfall, and open woodland ecosystems across the state.

Purshia tridentata is native to Idaho and occurs widely, particularly in southern and central regions. It grows on well drained, rocky or gravelly soils and is commonly found on slopes, benches, and open flats. Bitterbrush often grows alongside Bluebunch wheatgrass, Idaho fescue, sagebrush, juniper, and ponderosa pine. Its widespread distribution confirms that it is a naturally occurring species rather than an introduced plant.

Bitterbrush is a woody, multi stemmed shrub that can reach heights of up to ten feet. Its wedge-shaped leaves have three small teeth at the tip, which gives the species its name tridentata. In spring, it produces small yellow to cream colored flowers that attract native pollinators. Seeds are often cached by rodents, supporting natural regeneration.

Ecologically, bitterbrush provides critical benefits for wildlife. It is a primary winter food source for mule deer, elk, and pronghorn because it remains accessible and nutritious when other vegetation is limited. It also provides cover for birds and small mammals and improves soil fertility through nitrogen fixation.

In Idaho, bitterbrush is commonly used in rangeland restorationand habitat improvement. However, it is sensitive to overgrazing, frequent fire, and poor regeneration. Maintaining healthy populations is essential for sustaining biodiversity and ecosystem resilience across Idaho’s rangelands. A University of Idaho bulletin describing sagebrush grass habitat types in southern Idaho identifies antelope bitterbrush (Purshia tridentata) as a characteristic shrub in multiple shrub grass communities, reinforcing its native status and ecological importance in Idaho rangelands.

References

Utah Valley University. (n.d.). Purshia tridentata – Antelope bitterbrush. https://www.uvu.edu/crfs/native-plants/purshia-tridentata.html

Eastern Washington University. (2019). Purshia tridentata – Flora of Eastern Washington and adjacent Idaho. https://inside.ewu.pedu/ewflora/purshia-tridentata/

Hironaka, M., Fosberg, M. A., & Winward, A. H. (1983). Sagebrush-grass habitat types of southern Idaho (Bulletin No. 35). University of Idaho, Forest, Wildlife and Range Experiment Station. https://objects.lib.uidaho.edu/fwres/fwres171.pdf

Scotch Thistle: Spotting & Stopping this invasive in Idaho Landscapes

Have you noticed a massive, silver-green giant creeping into nearby pastures, roadsides, or even the back corners of your home garden? Scotch thistle (Onopordum acanthium) is making an aggressive push across Idaho landscapes, and this highly invasive weed requires early intervention.

Originally brought to the United States in the 1800s as a Mediterranean ornamental plant, it quickly jumped the fence. Today, it is an officially listed Class B Noxious Weed in Idaho, Oregon, and Washington. If left alone, it can easily form dense, virtually impenetrable stands that choke out native forage, block access for wildlife, and cause a major headache for homeowners.

Knowing the Lifecycle: Year One vs. Year Two

The secret to managing Scotch thistle is understanding how it grows. It operates primarily as a biennial plant, adapting its growth strategy based on the local environment:

• Year One (The Rosette): The plant spends its first year low to the ground, focusing energy on building a tough taproot. It forms a wide rosette of gray-green, velvety leaves covered in a thick mat of woolly hairs and sharp yellow spines. These rosettes can spread up to 2 feet wide.

• Year Two (The Giant): In its second year, the thistle bolts. It shoots up a heavily branched, winged stem that can tower over 8 feet tall and 6 feet wide. Globe-shaped, dark pink to lavender flowerheads emerge at the branch tips in mid-summer.

Why Is It Such a Problem?

A single, healthy Scotch thistle plant is capable of producing 8,400 to 40,000 slender, plumed seeds. These seeds are easily caught by the wind, hitch a ride on moving wildlife, or travel via contaminated soil, gardening equipment, and hay.

Once it establishes a foothold in wet meadows, dry rangelands, or disturbed garden soils, it quickly forms thick patches. Its formidable, spiny armor physically blocks animals from grazing and prevents access to waterways.

How to Control Scotch Thistle in Your Space

Tackling an infestation requires an integrated management approach combining mechanical, cultural, and targeted chemical methods.

1. Manual and Mechanical Removal

• Dig it out early: Small infestations are easiest to manage when the plants are still in the low rosette stage. Use a sharp shovel to slice the taproot completely below the soil surface.

• Gear up properly: The sharp spines are no joke! Always wear heavy-duty leather or chemical-resistant gloves and thick protective clothing to avoid painful punctures.

• Time your mowing: For larger patches, mowing can prevent seed production, but timing is everything. Mowing too early causes the plant to simply recover and flower closer to the ground. Mowing too late means cut flowerheads left on the ground can still successfully release viable seeds.

• Bag and trash: If the thistle has already started blooming, bag up and discard the cut flowerheads in the trash rather than composting them.

2. Cultural and Biological Methods

• Establish Competition: The single best long-term defense against thistle seeds is a dense, well-maintained lawn or pasture. Healthy, thick turfgrass or native groundcover will naturally outcompete invading seedlings.

• Managed Grazing: While there are currently no approved biological insect controls for Scotch thistle, goats will readily graze the prickly flowerheads, and sheep will sometimes feed on the younger rosettes.

3. Herbicide Control

When physical removal isn't practical, a targeted herbicide treatment may be necessary. Applications are generally most effective when sprayed during the active spring growth phase before the plant bolts. Remember to follow all pesticide safety protocols: wear proper protective clothing and avoid spraying during windy or excessively hot conditions to prevent chemical drift and volatility.

For specific chemical recommendations and timing tailored to your local county, consult the Pacific Northwest Weed Management Handbook or contact your local county noxious weed coordinator.

Remember Your Legal Obligations

Because Scotch thistle is on regional quarantine lists, it is illegal to buy, sell, transport, or distribute the plants, seeds, or wildflower mixes containing them. Keeping our boots, tools, and tires clean after visiting infested areas is a simple step that goes a long way toward protecting Idaho's beautiful open spaces.

---

Resources & Further Reading:

• Identification and Management of Scotch Thistle — Oregon State University Extension Catalog

• Noxious Weed Search: Scotch Thistle — Washington State Noxious Weed Control Board

• University of Idaho Extension — Landscapes and Lawns

Curled Tomato Leaves: Stress or Curly Top?

Seeing curled leaves on your tomato plants can be alarming, but curled leaves do not always mean disease. In many cases, the plant is simply reacting to stress.

Physiological leaf roll is a common response to growing conditions. It usually begins on older leaves near the bottom of the plant. The edges of the leaves cup upward and may roll inward, sometimes forming a tight, tube-like shape. Even though the leaves look unusual, the plant generally stays green, continues growing, and keeps producing fruit. Fruit quality and yield are usually not seriously affected.

Several things can trigger physiological leaf roll. Hot weather, drought, uneven watering, overly wet soil during high temperatures, heavy pruning, too much nitrogen, phosphorus deficiency, or a heavy fruit load can all contribute. Some tomato varieties are also more prone to leaf roll than others. The best response is usually simple: keep soil moisture as even as possible, avoid overfertilizing, and do not remove too much foliage at once. During extreme heat, temporary afternoon shade may also help reduce stress. There is no need to remove the plant just because the leaves are rolled.

Beet curly top disease is different. It is caused by Beet curly top virus and is spread by the beet leafhopper. Tomatoes are commonly affected, but peppers, beans, squash, table beets, Swiss chard, melons, cucumbers, and many weeds can also serve as hosts.

Curly top causes more than curled leaves. Infected plants may become yellow and stunted. Leaves can look thick, leathery, twisted, or brittle, and the veins may turn purple. New growth may be distorted, fruit production may slow or stop, and young plants can die. Unlike physiological leaf roll, plants infected with curly top do not recover.

Take a look at the whole plant before deciding what is wrong.

Is the plant still green and growing normally, with curling mainly on the older, lower leaves? Is it still setting and ripening fruit? That points more toward physiological leaf roll.

Is the plant stunted, yellowing, brittle, or declining? Are the newest leaves distorted? Do you see purple veins, leathery foliage, or very little fruit? Those symptoms are more concerning for beet curly top.

Plants suspected of having curly top should be removed because they will not improve. Managing nearby weeds may help reduce possible host plants. Young transplants can also be protected with row cover or shade cloth while they are becoming established, as long as row covers are removed when pollination is needed.

The bottom line: Leaf curl by itself does not equal curly top. Look at the plant’s color, growth, leaf texture, fruiting, and overall health before reaching a conclusion.

Interested in learning more?

• University of Idaho Extension — Physiological Leaf Roll of Tomato
• Oregon State University Extension — Physiological Leaf Roll of Tomato
• Utah State University Extension — Curly Top of Tomato