A rust gall on juniper with spore “horns” just starting to emerge. As soon as it rains after this point, the “horns” turn gelatinous and bright orange. Photo: M. Talabac
Q: I heard rust fungus can infect junipers but they aren’t worth spraying to treat. Is there anything else I can do to reduce the fungal spread from them to my other trees?
A: If you see and can reach fungal galls on the branches, clip them off. Some rust fungi (though not all) create a gall on their juniper hosts. Plant galls are tumor-like in that they’re clusters of malformed tissue, often in response to a pest or (in this case) an infection. When the weather starts to be consistently mild in spring and we receive enough rainfall, the galls where the fungus is spending the winter will begin to exude their spores.
These rust spores blow on the wind or wind-driven rain to vulnerable host plants like various members of the rose family. In our gardens, this includes apples and pears, hawthorn, serviceberry, quince, and crabapple. Fungus spores are extremely tiny, so how will you know what to look for? If the gall is producing orange goo, you’re missing the window since spores are already being dispersed. Ideally, remove all visible galls before this point, while they’re still hard and dry. Now is an excellent time to inspect junipers on your property for galls. Trim them off with hand pruners and toss them in the trash (don’t compost).
This is not a foolproof method for eliminating the risk of rust infection on other plants this year, but it certainly could help reduce the disease pressure. Fortunately, infections like cedar-apple rust, while an aesthetic nuisance from time to time, generally don’t cause serious damage to all hosts, though they can be more serious for some, like apple.
By Miri Talabac, Horticulturist, University of Maryland Extension Home & Garden Information Center. Miri writes the Garden Q&A for The Baltimore Sun and Washington Gardener Magazine. Read more by Miri.
Have a plant or insect question? The University of Maryland Extension has answers! Send your questions and photos to Ask Extension. Our horticulturists are available to answer your questions online, year-round.
Speedwell is a winter annual weed. It will end its life cycle and die naturally once we have consistently warm temperatures. Photo: G. Rinehart
The warmer-than-normal weather during February had many people thinking about an early start to lawn and garden season. However, as temperatures have dropped and been below normal for much of March, it looks like we may have a couple more weeks before lawns really start growing. Lawn growth and crabgrass emergence are related to soil temperature, which is slower to change than the air temperature. While I have heard reports of soil temperatures topping out in the mid-50s for a day or two, it’s important to remember that in order to germinate crabgrass needs soil temperatures around 53-55⁰ F sustained for 5 days. These two things lead to a few questions, particularly pertinent this year when February felt like March and now March feels like late February.
Should I fertilize my lawn now?
While the legal window for applying fertilizer to lawns in Maryland began on March 1, that doesn’t necessarily mean you should fertilize your lawn just yet. Unless the grass is actively growing (which is dependent on warmer soil temperatures) it likely won’t take up and use the fertilizer—so you are better off waiting until the lawn is actively growing. Temperatures consistently around 60 and enough growth to warrant a second mowing are pretty good indicators of this. Keep in mind that if you fertilized your lawn in the fall you can probably wait until after the “flush of growth” in the spring (usually April/early May) and then schedule your spring fertilizer application for after that “flush” and leading into summer—usually around mid-late May. If you didn’t fertilize last fall it is tempting to try to “jump-start” the lawn in early spring with a fertilizer application, but hold off until the soil temperatures are consistently warmer and highs are around 58-60⁰ F on a regular basis.
Should I apply crabgrass pre-emergent now?
I would wait until soil temperatures are 53-55⁰ F sustained for 5 days. Keep in mind that your best defense against crabgrass is a dense turf that crowds out crabgrass seedlings. So, if you have good turf density and mow at 3” or higher, your overall crabgrass pressure should be lower anyway. The typical recommendation is to wait until the forsythia is “half green-half gold” (or even a little earlier), but with the warm February we had, that indicator may or may not be as accurate this year. You can check soil temperatures for your location at the following website: https://www.greencastonline.com/tools/soil-temperature.
Is there harm in applying crabgrass pre-emergent too early?
Probably not, unless it’s applied several weeks early and the product starts to break down before crabgrass even starts germinating. If you want to maximize the period of time your crabgrass application is effective, wait until when conditions are conducive to crabgrass germination and then apply it.
Roughstalk bluegrass (Poa trivialis) is a cool-season weed that shows up in early spring. If you only have a few patches, you can dig them out by hand (including the roots) and overseed to fill in the bare spots. Photo: G. Rinehart
On another note, this is now the time of year when many winter weeds become more noticeable as they are likely producing flowers and setting seeds. While you can apply selective products to control these weeds, remember that these winter annuals like chickweed, purple deadnettle, speedwell, henbit, etc. are almost at the end of their lives and will die naturally once we have consistently warm temperatures. Another weed often noticed this time of year is the grassy weed called roughstalk bluegrass (Poa trivialis). Seeds of this grass are often a contaminant in turfgrass seed mixes (the cheaper the seed, the more likely you will have weed seeds) and this grass starts growing much earlier than tall fescue. As the temperatures warm, it is not as aggressive and noticeable. There are few selective control products that are labeled for roughstalk bluegrass and they tend to be restricted to professional sites and/or are expensive. If you only have a few patches in your lawn, digging these out (including the roots) and then re-seeding the spot with a soil-tall fescue mix is the best control approach for most homeowners.
With spring coming up, many of us are already starting to get our yards and gardens ready for the growing season. Among the activities we may take on, there can be the managing of branches, sticks, and wood that may have been trimmed from trees and shrubs in the fall, over the winter, or just recently. In today’s post, I want to talk about how to integrate these resources into our green spaces, to support wildlife and the natural services they provide.
Wood and stick piles can provide welcoming habitat to beneficial organisms. Photo: A. Espíndola
Increasing the diversity of our green spaces
In several of the posts that we publish on this blog, we recommend different actions that can be taken to increase biodiversity in our green spaces (see local ecotype plants, helping pollinators in small green spaces, and conserving parasitoids for some ideas). We know that increasing biodiversity improves the ability to control and restrain pests, increases wild and crop plant pollination, and in many cases leads to better soil quality. Among these practices, there is one that increases the physical complexity of our green spaces, providing nesting, shelter, and food resources to beneficial organisms. The practice I’m talking about consists of building wood and stick piles that can be established in our green spaces. The idea behind this practice is to create a space where birds, small mammals, insects, and even pest predators can find their preferred resources, and thus be attracted and present in our environments (learn more about the landscaping rationale for using dead wood).
What organisms are attracted by these piles?
Depending on the size of the pile and its composition (e.g., large logs, smaller sticks, a mix of them), different organisms will be attracted and may establish themselves in our green spaces. The presence of a mix of logs and sticks usually attracts birds, which may nest within the pile or may just spend time within the pile searching for food or finding shelter at different points during the day. These birds will certainly contribute to increasing the diversity of animals present in our green spaces and can also in some cases participate in the control of insect pests that we may not want in our gardens and yards.
Carolina wrens are very attracted to shrubby habitats, meaning that piles of wood and brush represent a great way to provide resources to these little cute birds who in turn can help us keep herbivore populations in line. Photo: Shenandoah NP.
Other animals we can observe in these piles are a variety of insects then may be associated with the decomposition of wood or that may use wood as a nesting or overwintering resource (e.g., bees, solitary wasps). While the former can help recycle the wood material and reintegrate it into the habitat, the latter may participate in the pollination of plants and crops that we may grow in that area or predate on unwanted pests.
Similarly, ground-dwelling invertebrates like millipedes and ground beetles can also find shelter under these piles, while the brush can also contribute to the nesting of pollinators such as (ground-nesting) bees, the overwintering of some butterflies and moths, and help improve the quality of the soil in that part of our yard.
Larger organisms may also be attracted to these piles, such as small mammals, amphibians, and even reptiles. Although we may tend to dislike these groups of animals, many of them feed on unwanted soil organisms and may help with soil quality, while others can actually control vermin through their predatory abilities. This is particularly the case of snakes that may find shelter in these spaces, which, while harmless to humans (the vast majority of snakes in Maryland are non-venomous, readily feed on rats and mice that may be present around the house.
A mix of thick and thin pieces of wood can provide a diverse habitat to many different organisms. Photo: A. Espíndola.
How to build these piles?
These piles can take many different shapes and sizes, which depend in part on the materials and space available. When very large spaces are available (e.g., in the woods), it is recommended for these piles to be relatively large – at least 10 to 20 feet in length, and up to 8 feet in height (read more about these larger brush piles). In smaller spaces such as in urban or suburban gardens, these piles can be much smaller, occupying areas that may not be regularly used for other purposes. In all cases, it is ideal to build these piles using a combination of different types of materials, such as twigs and branches of different thicknesses, some logs, and even some branches that may still have dead leaves attached to them…always using healthy materials.
An important consideration when putting together these piles is that they should not be built leaning on or very close to wood-based structures or the foundations of our buildings. This is because of the potential risk of termite infestations of buildings if the piles are not physically separated from them. However, it is important to stress that establishing these piles has not been shown to be associated with higher termite infestations if the pile is not in contact or very close to the built structure. (You can read a very good discussion about mulch and termites from Iowa State Extension).
So, as you work on your spring garden, I encourage you to think about plant stems, logs, and branches not as waste that needs to be cleaned up, but as beneficial resources that you can incorporate into your available space.
By Anahí Espíndola, Assistant Professor, Department of Entomology, University of Maryland, College Park. See more posts by Anahí.
Anahí also writes an Extension Blog in Spanish! Check it out here, extensionesp.umd.edu, and please share and spread the word to your Spanish-speaking friends and colleagues in Maryland. ¡Bienvenidos a Extensión en Español!
In this month’s episode, we are talking about container gardening with Ashley Bachtel-Bodkins, Senior Agent Associate and Master Gardener Coordinator for the University of Maryland Extension in Garrett County. If you are limited on space and time, a container garden may be a perfect way to add in the garden you’ve always wanted. We talk about picking the correct size container for your plant needs, drainage tips, and growing media.
We also have our:
Native Plant of the Month (Sweet Bay Magnolia, Magnolia virginiana ) at 26:00
Bug of the Month (Spongy moth, Lymantria dispar) at 30:45
Garden Tips of the Month at 38:45.
If you have any garden-related questions please email us at UMEGardenPodcast@gmail.com or look us up on Facebook.
The Garden Thyme Podcast is brought to you by the University of Maryland Extension. Hosts are Mikaela Boley, Senior Agent Associate (Talbot County) for Horticulture; Rachel Rhodes, Agent Associate for Horticulture (Queen Anne’s County); and Emily Zobel, Senior Agent Associate for Agriculture (Dorchester County).
April is National Garden Month! So Happy National Garden Month everyone. One of the clearest signals of spring is the emergence of spring ephemerals — daffodils, crocus, tulips… these bulbs are some classic examples — but we have so many more to enjoy! Our woodland wildflowers may be more subtle, but are no less impressive and are even more rewarding. This month we take a break from our garden and all the spring chores to talk about some of our favorite woodland spring ephemerals.
Ephemerals covered in this episode include Dutchman’s breeches, Virginia bluebells, mayapples, bellworts, spring beauty, Jack-in-the-pulpit, and pink lady slipper.
We also have our:
Native Plant of the Month (Sessile trillium) at 22:15
Bug of the Month (Termites) at 25:35
Garden Tips of the Month at (36:55)
If you have any garden-related questions please email us at UMEGardenPodcast@gmail.com or look us up on Facebook.
The Garden Thyme Podcast is brought to you by the University of Maryland Extension. Hosts are Mikaela Boley, Senior Agent Associate (Talbot County) for Horticulture; Rachel Rhodes, Agent Associate for Horticulture (Queen Anne’s County); and Emily Zobel, Senior Agent Associate for Agriculture (Dorchester County).
If your azaleas, rhododendrons, and other spring-flowering shrubs are growing too large, prune them after they bloom.
Thin out interior boxwood branches to improve air circulation and reduce disease problems such as volutella canker. Also, look out for boxwood blight.
Move houseplants outdoors after the danger of frost has passed. To avoid sunscald, first place them in a shady location and over a period of two weeks or so to gradually introduce them to more sunlight.
Pinch the blooms from flower and vegetable transplants before you set them out. This will help direct the plants’ energies to root development and will result in more productive plants. Gently break up the roots of root-bound transplants before planting.
Plant a butterfly garden – Butterflies add beauty and help pollinate flowering plants. A variety of nectar plants for adult butterflies and host plants (food) for the caterpillars will attract them. Milkweed species is a popular nectar and host plant for the Monarch butterfly.
Lawn mowing season begins in April. The height and how frequently you mow your lawn is very important. Cool season grasses such as tall fescue and bluegrass should be maintained between 3 – 4 inches for most of the growing season and no more than 1/3rd of the leaf blade should be removed at each mowing.
Fungus gnats are small, harmless black flies that hover around, breed in and feed on moist growing media. Be careful not to over-water houseplants. Growing media should be allowed to dry out before watering again.
Adult fungus gnat
“Harden-off” transplants one week prior to transplanting to toughen the plants and ready them for outdoor conditions.
