{"id":420783,"date":"2026-08-01T12:54:12","date_gmt":"2026-08-01T12:54:12","guid":{"rendered":"https:\/\/www.newsbeep.com\/us-ca\/420783\/"},"modified":"2026-08-01T12:54:12","modified_gmt":"2026-08-01T12:54:12","slug":"sun-water-and-pests-helping-roses-thrive-through-summer-san-diego-union-tribune","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/us-ca\/420783\/","title":{"rendered":"Sun, water and pests: Helping roses thrive through summer \u2013 San Diego Union-Tribune"},"content":{"rendered":"

For The Union-Tribune<\/p>\n

Sunshine and water are essential for people to survive and stay healthy, and they are just as important for roses. Together, sunlight and water are the foundation of rose health and make photosynthesis possible. Yet in summer, the sun that powers growth can also intensify heat stress, increase water loss, and encourage pest populations to thrive and reproduce quickly.<\/p>\n

Understanding how these factors work together helps rosarians make better choices about planting, watering, soil care and summer maintenance.<\/p>\n

Sunlight: The rose\u2019s power source<\/p>\n

Where a rose is planted matters. Roses generally perform best with at least six hours of direct sun each day. Morning sun is valuable in hot climates because it supports growth while reducing the intensity of afternoon heat. Some rose varieties tolerate partial shade, but roses grown in shade produce fewer flowers and are more vulnerable to disease.<\/p>\n

Sunlight powers photosynthesis, the process by which rose leaves use light to combine carbon dioxide from the air with water from the roots to make sugar. That sugar builds stems, leaves and roots, and it provides the energy the plant needs to grow and bloom.<\/p>\n

Fertilizers, compost and worm castings support rose health by supplying essential nutrients, but they are only part of the plant\u2019s growth equation. Much of a rose\u2019s structure is built from carbon, oxygen and hydrogen gathered from air and water. That is why adequate sunlight, healthy leaves and steady moisture are as important as good nutrition.<\/p>\n

\"ManyMany of Bill Radler\u2019s \u2018Knock Out\u2019 roses are known for their drought resistance. This is \u2018Double Knock Out.\u2019 (Star Roses)
\nWater: The partner to sunlight<\/p>\n

Water lets roses put sunlight\u2019s energy to work. It moves nutrients through the plant, keeps stems and leaves firm, and supports transpiration, the release of water vapor through leaf openings called stomata. Transpiration helps cool the plant and pulls water upward from the roots, but when soil moisture is limited, roses close their stomata to conserve water. This protective response also slows photosynthesis, reducing growth and flowering, especially during hot, dry or windy weather.<\/p>\n

Water deeply<\/p>\n

Light, daily sprinklings may seem helpful, but they encourage shallow roots near the soil surface, where heat and evaporation dry the soil quickly. Deep watering long enough to moisten the entire root zone encourages plants\u2019 roots to grow downward. Roses with deeper roots are better able to handle heat, drought and water restrictions.<\/p>\n

\"TheThe \u2018Brick House\u2019 Series of roses are outstanding roses with great resilience. \u2018Brick House Orange\u2019 has received the American Rose Trials for Sustainability (ARTS) award. \u2018Brick House Red\u2019 and Brick House Pink\u2019 have been trialed and tested by UC Davis for water efficiency and have been awarded the UC Davis Blue Ribbon for exceptional low water performance. (Star Roses)<\/p>\n

A soil probe can help show how deeply water has penetrated. Water when the soil is dry more than two inches below the surface. Water more frequently during hot or windy weather and do not wait for obvious stress such as drooping leaves or wilted blooms. If a plant shows stress, water immediately.<\/p>\n

Morning is usually the best time to water. During especially hot or windy weather, showering foliage with water can help cool leaves, and strong sprays of water can help control spider mites and aphids. Time application of water to avoid leaving foliage wet overnight. Contrary to myth, watering during warm weather does not scorch leaves; drought is a far more common cause of leaf scorch.<\/p>\n

Summer heat and rose stress<\/p>\n

The famous song tells us, \u201cSummertime and the livin\u2019 is easy.\u201d For roses and rosarians, however, summer can be challenging. Prolonged temperatures above 90 degrees make gardeners work harder and can push roses into heat stress. Blooms may be fewer, smaller, faded, crisped or less fragrant. Leaves may yellow, wilt, bronze, scorch, dry or drop. Growth may slow or stop entirely as the plant shifts from active growth to survival.<\/p>\n

During extreme heat, roses may enter quiescence, a temporary pause in growth that helps them conserve water and stored energy. Stomata remain closed longer, metabolic activity slows, and some roses may shed leaves to reduce water loss through transpiration. These responses can look alarming, but they are often survival strategies. Damage becomes more serious when heat lasts long enough for the plant to exhaust its reserves.<\/p>\n

\"'Pretty\u2018Pretty Polly Pink\u2019 is a polyantha rose bred by Dr. David Zlesak. Both \u2018Pretty Polly Pink\u2019 and \u2018Pretty Polly White\u2019 have earned the Blue Ribbon award from the UC Davis Landscape Plant Irrigation Trials for their exceptional performance on low water. \u2018Pretty Polly Pink\u2019,\u2018Pretty Polly White\u2019 and \u201cPretty Polly Lavender\u2019 have all received the ARTS (American Rose Trials for Sustainability) award. (Rita Perwich)
\nHelping roses through hot weather<\/p>\n

\u2022 Protect the roots: Several inches of organic mulch help retain moisture and keep soil temperatures cooler. Roses take up water most efficiently when soil temperatures are moderate, so mulch is one of the simplest summer protections.<\/p>\n

\u2022 Irrigate more often: During heat waves, add one or two irrigation cycles per week, then use a soil probe to confirm moisture has reached the root zone.<\/p>\n

\u2022 Build healthy soil: Organic matter improves soil structure and helps it hold the right balance of water, nutrients, and air around the roots. A soil test can help to prevent the tendency to overfertilize, which can harm both soil and plants.<\/p>\n

\u2022 Reduce competition: Nearby plants can compete for moisture, so give roses adequate space and keep weeds under control.<\/p>\n

\u2022 Provide temporary shade: Shade cloth can help during extreme heat. Container roses (especially those on a plant caddy with wheels) can be moved out of the hottest afternoon sun when needed.<\/p>\n

\u2022 Monitor containers and new plantings: Check containers daily in summer and water when the upper soil begins to dry. They may need daily watering during hot weather. Dark plastic pots can overheat roots; placing them inside decorative outer pots can help insulate them. Newly planted roses also need extra attention because their root systems are not yet established.<\/p>\n

\u2022 Preserve foliage: In hot weather, avoid cutting long stems when deadheading or bringing blooms indoors. Leaves cool the plant, shade canes and soil, and continue to support photosynthesis. To preserve foliage, remove spent flowers at the peduncle.<\/p>\n

\u2022 Avoid fertilizing and spraying: Do not fertilize or spray pesticides or fungicides during periods of extreme heat, regardless of whether the products are chemical or organic.<\/p>\n

\u2022 Consider growing rose cultivars that have been tested and have attained the UC Davis Blue Ribbon award for best low-water plants. These cultivars include \u2018Pretty Polly Pink,\u2019 \u2018Pretty Polly White,\u2019 \u2018Brick House Pink,\u2019 \u2018Kardinal Kolorscape,\u2019 \u2018Limoncello,\u2019 \u2018Icecap,\u2019 \u2018Pink Knock Out,\u2019 \u2018Double KnockOut,\u2019 \u2018Oso Easy Urban Legends\u2019 and \u2018White Drift.\u2019<\/p>\n

\"'Mutabilis'\u2018Mutabilis\u2019 also known as \u201cThe Butterfly Rose\u2019 has been designated an Earth-Kind Rose by Texas A & M University for its extreme heat tolerance and drought resistance. (Rita Perwich)
\nSummer pest challenges<\/p>\n

Heat does more than stress roses directly; it also creates favorable conditions for several summer pests. Grasshoppers, caterpillars, and rose slugs are some of the pests that challenge us in the summer garden, but the most troublesome summer pests are chilli thrips and spider mites.<\/p>\n

Both thrive in hot weather and reproduce quickly. Spider mites are tiny, and chilli thrips are not visible to the naked eye, so it\u2019s their damage that alerts gardeners to their presence.<\/p>\n

Chilli thrips feed on tender new growth, causing leaves to curl and pucker. Dirty brown streaks appear on leaf undersides, buds become deformed, and blooms look distorted or scorched. In hot weather, chilli thrips can complete a generation in as little as 11 days. Monitor new growth for chilli thrips\u2019 damage and remove suspicious growth promptly. During the hottest months, a useful mantra is: \u201cif in doubt, take it out.\u201d<\/p>\n

Unlike chilli thrips, spider mites usually begin on lower leaves and move upward, leaving foliage dry, bronzed, speckled, brittle or webbed. Check leaf undersides frequently, and when spider mites are present, use repeated hard sprays of water to limit damage and interrupt their lifecycle. Removing damaged lower foliage can also help reduce populations.<\/p>\n

\"'Pink\u2018Pink Knock Out\u2019 has received the prestigious UC Davis Blue Ribbon award for its extreme water efficiency and abundant blooms. (Star Roses)
\nSummer survival<\/p>\n

Summer can test both roses and gardeners. Roses may slow down in extreme heat, but with our steady support, close observation and timely action \u2014 watering deeply, preserving foliage, and monitoring pests early \u2014 they are better prepared to recover, grow, and bloom again when cooler weather returns. For gardeners, sun protection and hydration is essential especially in the summer, and the best time to garden is in the cooler hours of early morning and early evening.<\/p>\n

Perwich is a Consulting Rosarian, UCCE Master Gardener and author of \u201cNatural Rose Gardening: An Organic Guide to Amazing Blooms\u201d (Chelsea Green Publishing). Available for pre-order now at penguinrandomhouse.com\/books\/827874\/natural-rose-gardening-by-rita-perwich<\/a>. For more information and advice, visit rose-harmony.com<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"For The Union-Tribune Sunshine and water are essential for people to survive and stay healthy, and they are…\n","protected":false},"author":2,"featured_media":420784,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[28],"tags":[19505,181,74,76,75,420],"class_list":["post-420783","post","type-post","status-publish","format-standard","has-post-thumbnail","category-san-diego","tag-home-and-garden","tag-latest-headlines","tag-san-diego","tag-san-diego-headlines","tag-san-diego-news","tag-things-to-do"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/posts\/420783","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/comments?post=420783"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/posts\/420783\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/media\/420784"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/media?parent=420783"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/categories?post=420783"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/us-ca\/wp-json\/wp\/v2\/tags?post=420783"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}