No flowering rose bushes

Question: Hi!
I have about 25 rose bushes in my back yard. They get plenty of sunlight and water. The leaves are green, but they don’t produce any roses at all - they haven’t for the last 2-3 years. Any idea what the cause and cure might be?

responder: Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied May 10, 2024, 12:04 PM EDT
response: There are a number of possibilities, and some might be overlapping. One of our primary suspects with roses is deer...do any deer visit the yard or browse nearby overnight? They are very fond of roses, especially flower buds. If deer are a problem, a physical barrier (netting or a fence) or a chemical barrier (repellents that make the plant smell/taste bad to them) would be needed, though repellents are not always permanently effective.  Are the shrubs pruned back each winter (around February or so)? If not, that might be one reason they don't look very vigorous or balanced in shape. Shrub (non-climbing) roses are best pruned back to around 15-18 inches off the ground, more or less, each winter or very early spring so that they are stimulated to produce vigorous regrowth that should flower better than older wood.  Even setting aside the flowering issue, these plants look weak, like they are not growing well. You mention they get plenty of sun, but are they getting a full 6-8 or more hours worth of unobstructed summer sun? If not, that can reduce plant vigor and suppress bloom.  You also mention plenty of water...are they only being watered on an as-needed basis, based on checking the soil (and recent weather), or are they on some sort of irrigation cycle that runs on a programmed timer? If the latter, they may be getting over-watered, in which case root loss can result in branch dieback, sparser foliage, and poor/no bloom. Ideally, the soil near the roots should be checked about six inches deep and watered well only when it's becoming somewhat dry to the touch at that depth. Roses aren't very tolerant of constantly-damp soil, and extra watering will also leach certain nutrients out of the soil faster than watering only occasionally. While routine fertilization of roses should not normally be necessary in most soils, a laboratory soil test may reveal a deficiency in that planting area that might benefit from supplemental fertilizer. (We can help to interpret test results if you choose to send a sample to one of the labs on that page.)  The close-up of a blasted (dead) bud and dying stem could have been caused by an infection, but it's hard to tell from the photo. You can explore our rose diagnostic page to see if any of the ailments common to roses in our area seem to be affecting your plants. Some rose varieties are more vulnerable to certain diseases than others, though even resistant plants are not perfectly immune. If/when fungicides are warranted, they need to be applied preventatively to protect still-healthy growth, since they are not able to cure any existing disease. Several repeat applications per year, each year, are usually needed when a rose is particularly vulnerable to a given disease (black spot, for example). Weak or infected branches can be pruned off and discarded (don't compost).  Miri

responder: The Question Asker Replied May 10, 2024, 12:16 PM EDT
response: Wow… Thanks for the quick & thorough response!    Deer are definitely an issue – we get lots of them. It’s odd that they seemed to leave them alone for several years, but now they seem to have added them to their diet.    Also, I have not been cutting them back in the late winter. I’m guessing it would not be good to cut them back now?    I only water them when there is a long dry spell, but I’m glad to know that I should not risk over-watering them.    I might look into a soil test and the diagnostic page.    Again, thanks for your help!!    Best, Dan

responder: Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied May 10, 2024, 12:31 PM EDT
response: You're welcome!  Deer are probably the main factor in this case, then, though the other conditions we mentioned bear looking into, since more than one problem can still overlap and affect the plants. Deer can change habits as they become more over-crowded or desperate for food (they generally don't eat the invasive plants taking over local woodlands). Additionally, perhaps there were excluded from another property or area that they used to be able to browse in. Many deer in residential neighborhoods actually stay there their entire lives, rather than coming and going from wooded areas further away, so their diet depends on what they can find in home yards and wild spaces in between. You can try periodically spraying the rose foliage with repellents...it might be enough, at least to teach the deer that this isn't a plant they will find appealing. The trouble is that repellents wear off over time and in rain, and sometimes deer are too hungry to care, or just get used to the smell/taste and eat the plants they want to eat anyway, so it's an uphill battle.  Miri

responder: The Question Asker Replied May 10, 2024, 12:48 PM EDT
response: Thanks!!   Would it make sense to cut the bushes back now, or wait til nest February?   Best, Dan

responder: Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied May 10, 2024, 1:03 PM EDT
response: Apologies -- you can do some pruning now, but lighter than the wholesale cutback that's usually done in late winter...maybe shorten some stems a bit if they have sparse growth on the tips but are putting out new buds lower on the stem. You can also remove any spindly stems that are not putting out any leaves, if present. Otherwise, it might be best to wait to prune until they have more foliage and look lusher, since they need all the energy from photosynthesis they can get right now with such limited foliage.  Miri

responder: The Question Asker Replied May 10, 2024, 1:07 PM EDT
response: Thanks!!    Best, Dan

responder: Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied May 10, 2024, 1:43 PM EDT
response: You're welcome!

responder: The Question Asker Replied May 28, 2024, 5:16 PM EDT
response: Hey,    Just so you know, I took your advice regarding deer spray and fertilization and we are getting plenty of roses .    I have another issue:     We bought three small hibiscus trees last year. They produced a lot of flowers all summer. In the fall, we brought them inside, so they’d stay alive. They are alive and green, but they haven’t produced any flowers. Is there something we can do to promote flowering?  THANKS!! Best, Dan

responder: Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied May 29, 2024, 10:12 AM EDT
response: Glad to hear the roses are recovering.  We presume these are tropical Hibsicus (also called Chinese Hibsicus, Hibiscus rosa-sinensis)? We ask only because occasionally the hardy Rose-of-Sharon Hibiscus is trained into a tree form, though they are hardy shrubs. (They also don't start blooming until around midsummer or so.)  If these are the Chinese Hibiscus, they might need a little more time to resume blooming for this year. Are they situated in full sun or mostly sun? They grow and bloom best when getting enough light. Are the leaves still a dark green, or are they paler than you remember them being last year? If paler, or if they've shed a lot of inner foliage over time but not produced much new foliage yet, they may need fertilization (if you haven't applied any yet this season) to replace nutrients lost from the potting mix. In that case, any general-purpose flowering plant fertilizer should suffice, at the dosage recommended for container plants on the product label. Make sure they stay evenly moist (not soggy, but not so dry the plant wilts), since water stress can cause plants to abort flower buds mid-development.  Miri

responder: The Question Asker Replied May 29, 2024, 12:05 PM EDT
response: Thanks so much, Miri!!    Best, Dan

responder: Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied May 29, 2024, 12:10 PM EDT
response: You're welcome!

responder: The Question Asker Replied June 07, 2024, 1:16 PM EDT
response: Hi!    These hibiscuses are trained into a tree form. The trunk is “braided”; the total height is around 4 feet. The leaves look healthy; they get plenty of sun. I added Miracle Grow to the water. I am not over watering… Still no flowers on any of them…    Any suggestions?    Best, Dan

responder: Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied June 07, 2024, 1:24 PM EDT
response: Hello Dan,  Can you share photos of the plants? It's hard to guess at a diagnosis from the description, in that it doesn't sound like anything is wrong with the plants. Sometimes it can be hard to ascertain why a plant is stubbornly not blooming when it appears to be getting all that it needs, but we'll see if something jumps out at us in the photos. Can you relay the N-P-K analysis of the fertilizer you're using? (For example, 5-10-5.) If it's much higher on nitrogen (the first number in the series) than phosphorus and potassium (example, 10-3-2), maybe that's stimulating leaf growth at the expense of flowers.  Miri

responder: The Question Asker Replied June 07, 2024, 1:42 PM EDT
response: Hi!    Thanks for the quick response – You spoil me .    Here is a pic of one of the plants and one of the plant food. The plants are in the same soil that they came in when I bought them in the spring of 2023.  What do you think?  Best, Dan

responder: Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied June 07, 2024, 3:46 PM EDT
response: The pot they are planted in (that they were sold in, it sounds) might be restricting growth since they may be outgrowing the container. A plant this size might benefit from getting bumped-up into a container one size larger (or maybe a little bit bigger...a jump of one pot size generally involves a pot 1-2 inches wider in diameter). Whichever container you might choose to transplant them into, make sure it has at least one unobstructed drainage hole. The decorative pot it's sitting inside might actually work well, if it's available and drained. You can use regular (nothing special) potting mix to fill-in around the current root ball, making sure to loosen any tangled roots up a bit before putting it into new soil. Keep the depth at which it's planted the same as it is now.  The fertilizer shown is high in nitrogen, though that alone might not be a factor (or sole factor) in reluctant blooming. Normally, Chinese Hibiscus foliage is larger, denser, and darker green than what is pictured, so maybe the plants are getting a bit anemic, which could be related to root room as much as nutrient availability. Don't over-dose the plants (use whatever dilution and application frequency the package instructs), but the plant might need more time to put those supplemental nutrients to good use, since it looks like it needs to catch-up on foliage growth to support blooming.  We can't tell from the front label on the fertilizer if it contains "micronutrients," which include elements like iron, magnesium, and manganese. The "micro" in micronutrients refers to their proportional dosages for what plants need, not that they're any less important to overall health. Leaves yellower-green than is typical might be due to a near-deficiency in one or more of those elements. Some fertilizer formulations contain "micros" and others do not. In the ground, a fertilizer lacking them isn't usually a problem, since they are plentiful, but in pots, plant roots have limited resources and their depletion can be more likely. A change in soil acidity (pH) can affect nutrient uptake by roots, but we doubt anything has changed that drastically (if at all) in the potting mix to make this something to investigate. Potting mixes are generally formulated to be at the ideal level of slightly-acidic anyway unless an additive like lime or sulfur throws them off; not something we expect that you would have applied.  Are the pots being checked for watering needs daily? While they may or may not need daily watering at this point (depends on the weather and how root-bound they are), if a plant gets too dry too often, even if not yet wilting (or even if it recovers well after wilting), flower buds that might be in development can be aborted as a response to the stress. While this tends to happen on buds that are already large enough to be visible, it might be happening earlier in their development. The University of Minnesota says that high temperatures can contribute to bud drop in Chinese Hibiscus, but anecdotally they seem to bloom decently well during Maryland summers, so that might not be the sole factor.  Miri

responder: The Question Asker Replied June 07, 2024, 4:20 PM EDT
response: Thanks so much, Miri!! I will try to re-pot them and make sure they are watered. Best, Dan

responder: Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied June 07, 2024, 4:55 PM EDT
response: You're welcome.

responder: The Question Asker Replied June 08, 2024, 1:00 PM EDT
response: Hi,    I want you to know I really appreciate your help!    The attached pics are of my mailbox. I planted clematis at the base of the mailbox last year and it really didn’t do much: Very little growth and no flowers. This year it has really taken off, but there are no flowers.    My questions:    Does this look like it’s clematis? I’m wondering if perhaps another plant took over – one that doesn’t flower.If it IS clematis, what can be done to encourage flowering?    Please note that on either side of the clematis, there is a mum plant left from last fall.   As always, thanks for your help!  Best, Dan

responder: Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied June 10, 2024, 9:24 AM EDT
response: Hello Dan,  There is what appears to be a Clematis in the planting, but we can't tell what type. (There are hundreds of cultivars, plus one invasive species, Clematis paniculata.) Some bloom on new growth, some bloom on old growth, and some do both. Those that bloom on old growth can only be pruned just after flowering, or else their flower buds will be lost for the year. Those that bloom on new growth can be pruned in late winter and be fine, but that group only flowers in the summer, whereas old-growth bloomers flower in spring. Those that do both can flower in spring on old growth and then again in late summer or early autumn on new growth, so their pruning is more complicated.  The plant that made it to the top of the mailbox is not the Clematis. It looks like Oriental Bittersweet, an invasive species that we recommend be removed promptly before it establishes further. Control of this vine amid a desirable Clematis will be challenging, since it won't be easy to use herbicide to kill its roots. You may need to disentangle them and cut back all Bittersweet growth (and regrowth) as often as it appears until it dies out, which may take a while since it's a tenacious species. (We do have a web page about this weed, but at present, the website is temporarily down with a glitch, so we can't link to it here.)  For the future, we prefer that new questions (about unrelated gardening topics) be submitted in a new question thread, if possible. That helps us minimize scrolling through old correspondence and helps the question load faster, especially when there are lots of images. Plus, the question title also will correspond to the subject being discussed.  Miri

responder: The Question Asker Replied June 10, 2024, 10:55 AM EDT
response: Thanks!!  I will retire this thread  .  Best,Dan

responder: Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied June 10, 2024, 11:51 AM EDT
response: You're welcome.